Towing with T56

[CDeeZ]

If you search around on the internet, you will find a lot of people that claim that the T56 can-NOT tow....
Why they say this is beyond me, but I do have some theories....

1. A bunch of computer chair mechanics and self professed experts are simply regurgitating what they have read some other jackass post on the web.
2. Dodge stuffed the T56 in the SRT10 pickups but didn't give it a towing rating...... AFAIK this SRT10 is the only production pickup-truck to use the T56.

Regardless, this is an internet myth that needs to be debunked like the BS that it is......

So I took my 1990 Silverado with my T56 from Guthrie, Oklahoma to Arkansas City, Kansas to pickup and bring back a longbed F150 for a friend. I have not towed anything this heavy this far since the T56 swap
I did several years back. My little 1/2 ton with a T56 towed the other truck and trailer with pure ease. Torque multiplication is the key if you're going to tow with a T56 (or anything for that matter). My
torque multiplication comes in the form of 4.88 gears in my 14-bolt semi floater.

Now I prefer to be very scientific and quantative, but unfortunately I did not get the opportunity to run the whole rig over a scale.
I'm estimating the two trucks, plus the trailer, ramps, tools, etc. to easily be 10,000 LBS in total.....

With the 4.88 gears I was even able to keep the trans in 6th gear MOST of the time. I had to downshift into 5th to climb a few hills with all that weight, but all in all the truck performed like a beast.
I drove up to Arkansas City with just my truck. In Arkansas City, we hooked up the trailer, loaded the F150 on the back, and headed back to Guthrie, OK... Round trip burned up 1/2 a tank of gas... Not bad at all...

http://i1301.photobucket.com/albums/ag113/chase238/CAM00004_zpsa52dd6ff.jpg (http://s1301.photobucket.com/user/chase238/media/CAM00004_zpsa52dd6ff.jpg.html)

[Fast355]

If you search around on the internet, you will find a lot of people that claim that the T56 can-NOT tow....
Why they say this is beyond me, but I do have some theories....

1. A bunch of computer chair mechanics and self professed experts are simply regurgitating what they have read some other jackass post on the web.
2. Dodge stuffed the T56 in the SRT10 pickups but didn't give it a towing rating...... AFAIK this SRT10 is the only production pickup-truck to use the T56.

Regardless, this is an internet myth that needs to be debunked like the BS that it is......

So I took my 1990 Silverado with my T56 from Guthrie, Oklahoma to Arkansas City, Kansas to pickup and bring back a longbed F150 for a friend. I have not towed anything this heavy this far since the T56 swap
I did several years back. My little 1/2 ton with a T56 towed the other truck and trailer with pure ease. Torque multiplication is the key if you're going to tow with a T56 (or anything for that matter). My
torque multiplication comes in the form of 4.88 gears in my 14-bolt semi floater.

Now I prefer to be very scientific and quantative, but unfortunately I did not get the opportunity to run the whole rig over a scale.
I'm estimating the two trucks, plus the trailer, ramps, tools, etc. to easily be 10,000 LBS in total.....

With the 4.88 gears I was even able to keep the trans in 6th gear MOST of the time. I had to downshift into 5th to climb a few hills with all that weight, but all in all the truck performed like a beast.
I drove up to Arkansas City with just my truck. In Arkansas City, we hooked up the trailer, loaded the F150 on the back, and headed back to Guthrie, OK... Round trip burned up 1/2 a tank of gas... Not bad at all...

http://i1301.photobucket.com/albums/ag113/chase238/CAM00004_zpsa52dd6ff.jpg (http://s1301.photobucket.com/user/chase238/media/CAM00004_zpsa52dd6ff.jpg.html)

Not saying it can't be done, but compare the gears in a T56 to the gears in a NV4500 or even NV3500 and you will understand why they say don't tow with them.

[CDeeZ]

Yes the New Venture boxes have a much shorter 1st gear to help get the load moving. If you were going to be towing a lot of weight every single day then perhaps the NV would be a better choice. I don't know for certain, but I'm going to make a wild guess that few if any vehicles came with the NV3500 or NV4500 AND 4.88 gears.... What I'm getting at is while the T56 has a much taller 1st gear, this is overcome by the short geared 4.88s I'm running. I can start off in 2nd when I'm just cruising around cuz 1st doesn't last too long.

Honestly though, I think the consideration of only trans ratios by themselves is useless. And the consideration of just a ring and pinion ratio by itself is useless. IMO you have to look at the whole picture, being ALL of the ratios; the trans ratios, the R&P ratio, and how they compliment (or detract) from one another.

[greggbruceauto]

Not saying it can't be done, but compare the gears in a T56 to the gears in a NV4500 or even NV3500 and you will understand why they say don't tow with them.

um the t56 gears are at least as thick and actually have more teeth, thus more tooth contact. compared to a m-20 or 21 or even a 22, they are more heavy duty..... the 4500's are cast iron, and have slightly larger diameter gears....... it's probably more of a trade off --

Not sure I would trade a 4500 for a t56 in a 1 ton, but just saying the t56 is a rather stout trans and can handle a bunch of power.

[lionelhutz]

I was reading the post and found it a little disappointing you didn't at least have transmission oil temperature data to back-up your internet myth claim. Sure, it did the tow without failing, but the oil could have been running very hot (think >250*F), which won't be too healthy for the long term life of the transmission.

[CDeeZ]

I was reading all 13 of your posts and found it a little disappointing that you don't have anything of your own to contribute to towing with a T56.

I hauled that 11,000 LB rig over a hundred miles with no issues. Could I have been more scientific? Perhaps? Could I have installed NASA spec super secret laser beam transmisssion oil temperature monitors? Perhaps. Sometimes you just got to get the job done, and stop the endless mental masturbation of trying to over analyze every little thing.

You are right about towing potentially causing faster thermal breakdown of oils. This is one reason why we change our oils. The oil gets contaminated, and chemically and thermally breaks down, thus requiring it to be changed.

We're working on our screenplay of this episode of T56 towing, tentatively called On The Road 2.0..............

[lionelhutz]

So, since you don't like my post you attack me like an asshat???

Good job...

So when someone reads your claim that it's fine and tries to tow a load a 1000 miles and their transmission fails your answer will be that he should have changed the oil every 100 miles? If your transmission was cooking then you could have lowered the oil life from 10's of thousands of miles to 100's of miles.

Overall, your post claiming that your success means any worries about towing with a T56 are mindless is just more internet drivel since you have no real data to back it up. Don't bother coming back unless you have an oil temperature reading or an oil sample.

[CDeeZ]

I think it's funny how you come in here acting like some kind of authority on the matter, claiming that other people's experiences are null and void because they don't meet your expectations.

And you have resorted to name calling. Very mature. Very scientific. and Very informative.

I'm sharing my experience with others because it was a successful one, and there are a lot of posts scattered throughout the web of people saying you can't tow with a T56 for one reason or another....
Where in my post did I say that the oil should be changed every 100 miles? Your logic sucks. My answer would be, you should have done some more research, and not resorted to the lazy man's heurestic like you just did.

So what you're saying is real world experience in doing something is useless, that we should only ever theorize about it and try to pointlessly, endlessly quantify, organize, stratify it. Just get out there and do it and see what happens.

Ya know, it's a classic case of: it's not what you say but how you say it. You could have worded your first post a thousand other ways "That's an intersting find, but I would have really liked to see temp data!"

My post is real world experience. Actually getting off the computer and doing something rather than perpetuating mindless mental masturbation (your specialty obviously). Maybe you should try it sometime, you might rise above the ranks of a self professed expert.

YES, it would have been AWESOME to get some temp data. Relevant and useful, I agree with you there. Unfortunately, I didn't have the ability to do that this time. Maybe next time I will be able to. But for you to say that real world experience is useless? That's ridiculous.

[brian617]

Claiming that towing with a T56 is no different than a NV4500 is the same as saying towing with a 1/2 pickup is the same as a 3500 dually. Sure your 1500 can pull that same weight, but can you stop it in a safe distance if required? The gears in the NV are taller and wider, the mainshaft is much larger diameter and the counter shaft matches the rest of the components as well as larger bearings. Those are the facts.

[CDeeZ]

I didn't say it was the same as a NV4500 are you serious!?!?!

3/4 ton brakes on my 1/2 so no problems with brakes at all.................

I originally read (I believe on Keislers website?) that the T56 was SUPPOSED to be a truck trans, but they never did that and instead it ended up in the Viper before anything else.

[CDeeZ]

The T56 is probably not the trans for a 1 ton tow rig. But it's beefy. Even the earlier "weaker" T56 is still beefy.

　
　
http://i1301.photobucket.com/albums/ag113/chase238/T566_zps03fdf589.jpg (http://s1301.photobucket.com/user/chase238/media/T566_zps03fdf589.jpg.html)

http://i1301.photobucket.com/albums/ag113/chase238/T56_zps28941fbd.jpg (http://s1301.photobucket.com/user/chase238/media/T56_zps28941fbd.jpg.html)

http://i1301.photobucket.com/albums/ag113/chase238/T562_zpsc9656366.jpg (http://s1301.photobucket.com/user/chase238/media/T562_zpsc9656366.jpg.html)

[RobertISaar]

personal attacks end now.

you want to attack something, attack data.

[lionelhutz]

Rant and rave all you want, you still don't have any actual data that proves the transmission still operated safely during towing. In case you don't understand what I mean by safely I am meaning in an operating condition that will not lead to it's premature demise.

[brian617]

Need to invest in a leaf blower, wait is that a personal attack? I'm kidding :laugh: No hard feelings here.

[CDeeZ]

Oh there is data there in the form of real world experience. Hard to see from that ivory tower i know.

Leaf blower? :)

[lionelhutz]

Why don't you enlighten everyone and explain how your single experience towing 100 odd miles has proven that a T56 won't prematurely fail if you tow with it without some kind of data showing it was operating safely? For example, temperature data, wear data or oil analysis data that proves nothing wasn't being hurt during the tow.

[CDeeZ]

I'm sorry. It's not my duty to enlighten you.

I have towed MANY things with my truck since T56 swapping it. Did I bother to catalogue each instance with a full reportoire of data for you to review? No.

These are facts:

My fullsize truck, that wasn't supposed to have a T56 from the factory, now has it.

Scored a USED T56 on craiglist and installed it.

FIVE years later, after much daily driving and spirited driving ( I haven't been nice to my T56), and some occasional towing, still going strong with no sign of failure. That's not good enough of course. Not space age technology......




You're the one with the labratory obviously, why don't we use that for your uber scientific analysis?



Mrplow did a T56 swap before alot of us:

http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/95731-t56-6-speed-swap-2.html (http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/95731-t56-6-speed-swap-2.html)
But that's worthless too, there is no official NASA spec printout with special congressional authorization to verify it so yeah it's no good......

[lionelhutz]

And you are still continuing with the insulting bullying tactics. But then attacking the other person is the typical response from someone who can't argue facts...

Do you have any proof on how quickly the oil was being broken down?
Do you have any proof that the transmission wasn't overheating?
Do you have any proof you didn't cause some damage to a bearing or other internal part that will now fail prematurely?
Do you have any proof you didn't break through the oil film between the 6th gear set and cause a little gear face damage that will propagate into a failure?

You want to discuss some of the wording in your first post? Your opening claim was that you can tow with a T56. You posted that any internet post that says you can't tow with a T56 was BS. So, since you know these internet posts are myths you must know what is it capable of towing. So can you tow 10,000lbs 100 odd miles but only that much weight and that far? Can you tow 10,000lbs every day for thousands and thousands of miles if you wanted? Can you tow any weight any distance? What about the service interval? Do you change the oil at 1/2 the recommended service interval? At 1/4? At 1/10? What about which gears you should use for the weight you are towing vs the power the engine has? What about ambient temperature? Can it tow 10,000lbs without failing when it's 110*F out or only when it's 70*F out?

At the end of the day, all you proved was you were able to tow 10,000 lbs 100 odd miles without being broken down on the side of the road due to a transmission failure. Nothing more. Any claim you make beyond that is just as much speculation by you as the internet posts you insulted in your first post.

As for MrPlow. What gear does he tow in? Using 4th would be WAY easier on the transmission then 6th. Even 5th would be easier on it then 6th. He mentions a pump and oil cooler. So, does he have one or not? That would make a HUGE difference on the towing capacity of the transmission.

[CDeeZ]

It's called sarcasm. Maybe you should learn to recognize it. And then maybe not take yourself so seriously?
Let me restate this yet again
"
These are facts:

My fullsize truck, that wasn't supposed to have a T56 from the factory, now has it.

Scored a USED T56 on craiglist and installed it.

FIVE years later, after much daily driving and spirited driving ( I haven't been nice to my T56), and some occasional towing, still going strong with no sign of failure. That's not good enough of course. Not space age technology......

You're the one with the labratory obviously, why don't we use that for your uber scientific analysis?"
I think you grossly misinterpreted my post. Some of that might not be your fault beacuse this deal is a lot like text messaging. There is no context when you're not talking face to face.
Ang again here we go copying and pasting: that is not the only time I have towed with the T56 since swapping it. It was the MOST RECENT instance. So get off the 100 odd miles of towing like it's the only towing this trans has done.
The reccommended service interval for the T56 staight from GM is to only ever top off the trans if needed, not to ever change the fluid. Myself? I change it every 5,000 - 10,000 miles. Does it need it? Probably not. But I have the peace of mind of knowing that for a few bucks in fluid the trans should live that much longer.
At the end of the day people like you will always nitpick some little trivial detail and try to blow the whole thing wide open, because you have nothing better to do.
I have said multiple multiple times: unfortunately the only data I have on this one is real world experience. By itself it's not the be all end all but it does give an indication of what you can realistically do in the real world. It is, one piece of the puzzle figuratively speaking.
Mr Plow speaks of a pump and cooler. AFAIK, he never used one, just commented to the effect like "hey if you're going to run a T56 in a 6,000 LB bus like my suburban, and you want to do towing regularly of things in the neighborhood of 13,000 LBS; a cooler and a pump would be a good idea". Not sure what gear he towed in, I'm assuming he made use of either of the double ODs.
Torque multiplication is key
. If you gear your axle properly to match the deep ratios of the T56 and the tall tires typical of trucks, you can tow anythign WITHIN REASON. Before I had the 4.88s I run now, I had 3.08s from when the truck was an auto, and with the T56 and 3.08s: you had to slip the clutch alot in 1st to get going, and 6th was all but useless, and forget about towing with those 3.08s cuz it's not happening.
The T56 is not a towrig transmission. Noone has tried to say it should be used in semis and 1 tons and combines. But it is a beefy trans that can hadle alot of what is thrown at it, if you're smart about it.
I drive at least 200 miles every week for my job, if not even more than that. It was a little over a month ago that I drug this truck back. So IF, something was hurt from towing, I think it would have already reared it's ugly head.

[S10LS]

So whats the point of the thread? Are you recomending that people will have no issues towing heavy loads with the t-56? Or is it a thread saying I towed with my T-56? The 4.88 gear might help save the t56. But who wants to tow with 4.88 gears? I could tow 6 times the rated capacity with my old nv1500 as well. At least it has a towing rating. No data to back up any claim you are trying to make, without at least LONG term towing is not really that helpfull. If you are doing it to just mess around an see what it can take then thats cool. But to get your feelings hurt when someone is challenging your finding especially when their statement is that no full size truck came with one for towing is a bit rediculous. All kinds of data would be helpfull from exact combo you are running to the fuel mileage your getting, to a serious longevity test.

[S10LS]

"Torque multiplication is key". Probably the key to keeping it together. Keep the thread updated so we can see how it does.

[CDeeZ]

The point of the thread was just to show what I did. I'm not reccommending anyone do anything other than use common sense.

The 4.88s are perfect for a vehicle with a deep gearspread in the trans (T56) and tall tires 29" or above.

"But who wants to tow with 4.88 gears" Elaboration????

The fact that the T56 was not given a towing rating is kinda irrelevant I think, a simple quick search on google will turn up plenty of people who have towed with a T56, including Mrplow in his 6,000 lb tank.

There is data in the form of real world experience. I have towed a pile of axles, motorcycles, engines, etc. This was the most recent and probably the heaviest tow so I chose to report it. When did real world experience become "not-data"?


Like I said I've been beating on this craigslist T56 for 5 years and have done some occasional towing during that period so I think if towing was going to break this T56 it would have done that in the course of 5 years.


And as far as the oil analysis data and everything else you guys are talking about. Great idea. Do either of you work at Conoco or something because I don't have access to anything like that.


Fullsize trucks did come with the T56 , the SRT10. GM toyed with a concept truck that also used the T56 in a stripped down, vinyl floormat fullsize truck. (Never made full production unfortunately).


The drivetrain combo is a 350 TBI that I screwed together maybe 6 or 7 years ago. ~ 300-350 HP and 400-450 LB/FT est. Elgin cam, ported and polished heads, Ultimate TBI mods, AFPR, TBI and pod spacers, .060 over, HVOP, midlength headers with H pipe and full dual 3" pipes, ported and relieved oil return holes in lifter valley, 7427 PCM swap and DIY tuning. T56 trans obviously. 14 bolt semi floating 9.5" ring gear with 4.88s and Detroit TrueTrac. 3/4 ton brakes all around.

[EagleMark]

Watching trans oil temps while towing in 4th, 5th and 6th gear would at least say a lot of what the trans is doing with the load and if oil is being heated past it's tolerance.

Oil analysis can be mailed in by anyone to various companies for engines, not sure who does trans? Diesel shops regularly use analysis at service intervals to see what is wearing in motor.

[RobertISaar]

im'ma just do some math here, because i'm curious about this myself:

T56(no model specified, so i'll assume a 95ish LT1 F-body unit for gearing purposes):
http://i.imgur.com/f2mrl80.png

NV4500(i'll assume another 95 unit, MT8 RPO):
http://i.imgur.com/1e9czSM.png

it's too bad the graph function isn't working at the moment.... it's nice to visualize it as well.

but those are with the same 4.88 gears(and 28" tire). as far as the highway(55MPH) is concerned, 5th in both is 2350-2400 RPM, but the T56 has the option of 6th gear when possible, RPM would drop to just over 1600.

to match the same RPM as the T56 6th gear, the NV4500 would need to use 3.35 final gears. i don't know if this is realistic/normal or not.
http://i.imgur.com/8OYRyXH.png

anyways, from a purely mathematical perspective..... the T56 gear spacing is VERY nice, has fairly consistent ratio changes, which would certainly help keep the engine in its powerband at any time. the NV4500: not so much. shifting at 3000 will land you anywhere from under 1500 to 2200 in the next gear. some gears, you would need to wind it out a lot further than others to keep the engine from dropping to too low of a speed in the next gear.



as far as the hardware holding up, i won't speak of it, neither the T56 or the NV4500 is anything i have experience with nor knowledge of. i'm much more interested in seeing how to stuff a T56 into a 4WD S10 chassis with a heavily boosted V6 in front of it for my personal use.

[CDeeZ]

I would think that any place that analyzes oil should be able to do trans fluid as well, it's still oil after all, just with some hydraulic fluid mixed in as well.
My T56 is the 95+ model with the 2.66 1st. I believe that is the most common gear spread for T56s, not sure on that one though.
As that shows, the NV4500 has that short 1st gear which would be very helpful in getting a very heavy load moving, and as you pointed out, 5th is nearly identical.
"
anyways, from a purely mathematical perspective..... the T56 gear spacing is VERY nice, has fairly consistent ratio changes, which would certainly help keep the engine in its powerband at any time. the NV4500: not so much. shifting at 3000 will land you anywhere from under 1500 to 2200 in the next gear. some gears, you would need to wind it out a lot further than others to keep the engine from dropping to too low of a speed in the next gear."
The same closely spaced gears that are enjoyable to just drive/hot rod around in are also helpful when towing because as you stated, it will help keep the engine in the fat spot of the powerband each and every time you shift.
The NV and T56 are both great gearboxes. Just depends on what you want to do the most. Do you want mainly fun cruising from a brick-shithouse-tough trans that shifts like a sports car and can still do some occasional towing. OR, do you want a true truck trans with that granny 1st gear to really get the load moving. The NV is a wonderful box and certainly has it's place, but it will never have the shift feel and shift throws of a T56 (obviously). Don't anyone misunderstand me, the NV is a great box.
　
There are/have been/will be some companies offering 4wd T56, not sure if it's available yet? Anyways I have thought much about a 4wd T56 myself, and I know there are people out there who have done it; I believe it usually involves running a divorced T case but check this out
http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&docid=9Wt6w2tujfFoNM&tbnid=Lrp-I4q_SnSRUM:&ved=0CAUQjRw&url=http%3A%2F%2Fgrassrootsmotorsports.com%2Fforum %2Fgrm%2Fcyclonetyphoon-clone-on-a-budget%2F22144%2Fpage1%2F&ei=LWWvUpqZGfTTsAStp4CgDA&bvm=bv.57967247,d.eW0&psig=AFQjCNHrmxo31kDBz7PBX5FU3MmghzvSBQ&ust=1387311334351554 (http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&docid=9Wt6w2tujfFoNM&tbnid=Lrp-I4q_SnSRUM:&ved=0CAUQjRw&url=http%3A%2F%2Fgrassrootsmotorsports.com%2Fforum %2Fgrm%2Fcyclonetyphoon-clone-on-a-budget%2F22144%2Fpage1%2F&ei=LWWvUpqZGfTTsAStp4CgDA&bvm=bv.57967247,d.eW0&psig=AFQjCNHrmxo31kDBz7PBX5FU3MmghzvSBQ&ust=1387311334351554)

[steveo]

i can stab my tire with a knife several times without it failing, does that mean

- it definitely wouldn't fail in short order if i keep doing it?
- someone else with a different knife might puncture it on the first try?
- you were perhaps, even subconsiously, stabbing it like a wuss trying to prove your point?

using the thought process "i've done it a few times and it hasn't broken yet" as a metric for component strength and longevity...... is that good?

just sayin'

[CDeeZ]

http://i.imgflip.com/5icvh.jpg (http://imgflip.com/i/5icvh)via Imgflip Meme Maker (http://imgflip.com/memegenerator)

[EagleMark]

Please don't make me delete this thread! :thumbsup:

[CDeeZ]

4+ years later..... I finally had to take the T56 out to take it apart. But not for any reason related to towing with it, which many internet "experts" say you simply cannot do. The stock stamped steel 3-4 slider keys finally broke, a common problem with T56s that can happen at any time. When this happens it gets stuck in 4th gear. Everything else inside the gearbox looks perfect, bearings, tooth contact patterns, races, synchros etc.

I bought this used T56 secondhand on CL 8 years ago, beat the shit out if it in this pickup behind a SBC for years. Lately, I have been thrashing it some more behind my S475 turbocharged LQ4 (still in the same heavy AF truck). I also towed with this trans in the truck a few dozen times after the original post, didn't get to run it over a CAT scale every time but it was always around the ballpark of 11,000+ pounds based on the occasions that I did hit a scale.

Since I'm in the gearbox to replace the broken slider keys I'm bulletproofing it at the same time, building a T56 hybrid. Credit for this info goes to this guy here:
https://www.eecis.udel.edu/~davis/z28/2010/100201_LS7T56/800-1000hp_rated_LS_Fbody_T56.pdf

SSR 32 spline mainshaft, solid billet slider keys, bronze fork pads, triple/double cone synchros, TH400 slip yoke. I'm also going to TIG weld a -6AN fitting onto the case for a fluid/sprayer pump. This will eventually get hooked up to a pump which will spray oil directly at the headset gears. Should be a good addition when I start to crank up the boost in this heavy groundpounder.


https://i.imgur.com/06jfEZ6.jpg
The trans on the bench ready for teardown


https://i.imgur.com/Nkh6tcV.jpg
Everything inside looks perfect. It's just the goofy stock stamped steel keys that forced me to take it apart.



https://i.imgur.com/Y9cZgJg.jpg
The F-body gearset is sticking in the bench. Corvette input in the front cover, F-body laying next to it. Corvette and F-body clutsters laying next to each other.


https://i.imgur.com/CQV65Vj.jpg
SSR oil seal, bronze fork pads, and billet keys. Also a 3/16 loose ball bearing for the upgraded 1/2 snychro retainer.


https://i.imgur.com/4nzwzuV.jpg
SSR mainshaft, VSS reluctor, 1/2 synchro retainer, small input bearing, TH400 yoke, and steel Viper 3/4 fork.


https://i.imgur.com/lkYC7C6.jpg
Not a lick of unusual wear anywhere in the whole thing.


https://i.imgur.com/ZudKOmY.jpg
The C5 Corvette donor trans for the hybrid build.


https://i.imgur.com/U9tsxKZ.jpg
Corvette and Fbody T56 torn down. There is a 3rd T56 floating around the shop somewhere haha.

[woody80z28]

Pretty cool. I've had my FWD 5spd apart a million times but haven't opened up my T56.

Glad to hear about the towing. The NV4500 in my truck is a beast, but it's good to know I can tow tools and tires if I ever do Drag Week in the Camaro.

And as far as ratios, the T56 is heaven compared to the NV4500. The splits on the 5spd drive me crazy. Pulling hills with a trailer it always wants to be between 4th and 3rd. And you really do have to wind out the first few gears so the next one doesn't fall on its face. Although the granny low can be nice sometimes. I even put a rocker switch in the front axle actuator so I can have 2LO. Just let the clutch out and it creeps.

[notime2d8]

You didn't put a caliper on those parts after towing to make sure that they were within spec...not scientific :laugh:. Thanks for the info. I've never seen those upgrades for the T56.

[CDeeZ]

Pretty cool. I've had my FWD 5spd apart a million times but haven't opened up my T56.

Glad to hear about the towing. The NV4500 in my truck is a beast, but it's good to know I can tow tools and tires if I ever do Drag Week in the Camaro.

And as far as ratios, the T56 is heaven compared to the NV4500. The splits on the 5spd drive me crazy. Pulling hills with a trailer it always wants to be between 4th and 3rd. And you really do have to wind out the first few gears so the next one doesn't fall on its face. Although the granny low can be nice sometimes. I even put a rocker switch in the front axle actuator so I can have 2LO. Just let the clutch out and it creeps.

The T56 is really quite easy to navigate around once you're in there. I think the gurus on the mountain who came in here years ago talking shit are either as dumb as I think they are, or they missed the point of the post. If you're building a dedicated 1 ton tow rig is the T56 the transmission of choice?? Not really.... But if you need to tow something with it can it take it??? Absolutely. It really is a robust transmission.

Yes the close ratios of the T56 are just great for any kind of use, be it dragging a junked out 280z to the crusher or waxing that ass of the prevalent obnoxious Mustang driver.


You didn't put a caliper on those parts after towing to make sure that they were within spec...not scientific :laugh:. Thanks for the info. I've never seen those upgrades for the T56.

:rofl:

The thing that does suck about the T56 game is now that Tremec bought the T56 design from Borg Warner, and has subsequently ended the production of the T56, the transmissions themselves and parts are going to get harder to find.....

Tremec is the only game in town and they know it. They would like to force the TR6060/Magnum on all of us who want a six speed manual. I almost bought one just for the convenience of bolting it in and go. But the more I started to look into it, I found that it wouldn't be a upgrade in my opinion.

The TR6060 has bigger gears and bearings, so since the same basic case dimensions were used, something had to give.... The synchros were it. The clutching teeth are much smaller in a TR6060 which means it is MUCH less forgiving of missed shifts.... I don't really believe the bearings and gears to have been a weak link with the T56, it was just the goofy stuff: plastic fork pads, stamped steel slider keys, aluminum 3-4 shift fork that was prone to bend......

SEE POST #14 below:

https://ls1tech.com/forums/manual-transmission/1206190-t-56-magnum-vs-tr6060.html

I purchased all the parts to beef this thing up from the Gearbox.... They, like many other companies are advertising their slider keys as "billet"..... One of them broke in my hand, right out of the box..... It looks more like powdered metal to me...... I really hope someone in the aftermarket steps up and starts supplying T56 parts including some real actual billet slider keys instead of the powdered metal ones that every company is trying to pass off as something they are not.

[woody80z28]

I have the LT1-style in my Camaro, so most of the cross-swapping stuff from your other post isn't of use to me, but I have seen the other upgrades you mention as part of the build options for a Tick Performance rebuild. I've thought about doing that down the line, before I add nitrous. My 383 will be about 550hp N/A, so I think the stock 48k mi trans will live behind it. But I think some nice, violent nitrous shifts would probably do it in.

[CDeeZ]

If you tackled that 5 speed FWD I'm sure the T56 would be cake for you. I have no FWD experience but I'm thinking it would be a bit more challenging. Yeah the main thing I wanted was a 32 spline mainshaft since this truck is heavy and now has a turbocharged 6.0 LS bolted to it.... I'm only going to keep cranking up the boost eventually so I figured I might as well bomb-proof this thing. Yeah there are guys who have pushed a bone stock T56 into the 9s in the quarter so I don't think you'll have too much problem. I would run it till it breaks then fix it and beef it up where ever you want. I have two other T56s and I'm thinking about having one of them faceplated for use in my 62 Chevy II. Ever look into that?

[woody80z28]

From what I've read, face plating makes them shift higher, but be a bitch on the street. Mine will see lots of street duty (Power Tour etc) and I don't think that's the route I want to go. I did see an Australian sequential shifter you can pair with a face plated trans that would be badass for drag duty. Also seems like a pain in the dick on the street though.

[lionelhutz]

I can show you pictures of a T56 from a Corvette with gear teeth all broken. I didn't find anything else broken but the gear teeth. But hey, they never break and can take tons of abuse, right?

I'd rather be dumb than a name calling piece of shit like you...

[CDeeZ]

**** Autistic screeching ****

No one was talking to you. You may now resume jacking off and wishing you had a T56.

[CDeeZ]

From what I've read, face plating makes them shift higher, but be a bitch on the street. Mine will see lots of street duty (Power Tour etc) and I don't think that's the route I want to go. I did see an Australian sequential shifter you can pair with a face plated trans that would be badass for drag duty. Also seems like a pain in the dick on the street though.

I don't think it would be bad on the street. There are guys on tech who are running them and all the ones I've read about say that they would never have a synchronized box again after going that route. Basically what it would be like is similar to a motorcycle transmission which uses dog engagement. So in a car, that would be the only tradeoff as far as I can tell, it would no longer be silky smooth and quiet like with synchros, but a positive audible "CLUNK" when you engage gears.

[lionelhutz]

Your shit is nothing special. I have 3. One is just good for a few parts now.

[CDeeZ]

Looks like lionelhutz wandered off from camp and forgot to take her meds again.

[lionelhutz]

https://i.imgur.com/lkYC7C6.jpg
Not a lick of unusual wear anywhere in the whole thing.



You "perfect" bearing ~only~ appears to have discoloration from mild overheating or very slight metal to metal contact. No big deal though, not like it's failed ~yet~.

This is what that bearing actually looks like when it doesn't have doesn't have any unusual wear.

[CDeeZ]

It's stained. Not discolored from heat.

These social forums provide a useful function. They let these poor people who would otherwise have no voice sound off, and feel important. All the while people are laughing behind their back.

[lionelhutz]

Try again. Lubrication stained is the first sign of a bearing running too hot.

And yes, I do keep laughing at how pathetic you are. You actually posted proof of how stupid your claims are.

[CDeeZ]

Nope, it is you who should try again. When I said normal wear, I think you missed the fact that this bearing is original to a gearbox that started off as an LT1 box, circa 1995. It has likely never been rebuilt and I bought it second hand on CL 8 years ago. I put 250,000+ miles on it myself, who knows how many were put on it before I got it.

Your name is fitting, for the most part. I googled it to see and it's a character from the Simpsons. Here's a synopsis of the character from a few paragraphs in:

"Hutz is characterized as both a grossly incompetent lawyer and an unethical individual in general...."

The incompetent part fits you to a T!!!! However the lawyer part is likely not fitting.... I'm sure a genius like you has never attended college, let alone earned a JD. In fact, I would not be the least bit surprised if you're a high school flunkie.

I make no claims, I report real experience. You are a sideline shit talker. But this is verrrryyy entertaining!

[lionelhutz]

LOL Yup, no surprise you'd just keep making up bullshit excuses for the fact the bearing is clearly showing the initial signs of overheating. When I posted it is not normal wear, I think you missed the OBVIOUS FACT that overheating is not normal wear, genius.

One thing you can always count on is that the internet idiot with absolutely no leg to stand to on will fall back to pathetic personal attacks.

[CDeeZ]

Ok LOL

It's hilarious how you project your own flaws on others LOL. You're the one who came in here and started name calling, don't you remember? I use a little sarcasm and tongue in cheek satire and it STRUCK A NERVE with you :rofl:

You're the one who chose that name for yourself, so why are you getting mad at me?? :wtg:

[lionelhutz]

If you could count, you'd know that post 31 comes before 36.

"talking shit are either as dumb as I think they are" isn't sarcasm or tongue in cheek satire.

[CDeeZ]

HAHAHAHAHAHAHAHAHAHAHA!!!!!

If I could count?!?! There you go projecting again lionel-hun! It looks like it is in fact YOU who cannot count! BWAAAAHH-HAHAHAHAHAHAHAHA! Seriously, STOPIT! You got me rolling over here!!!! :laugh::laugh::laugh:

And.... You prove my point yet again.....


"talking shit are either as dumb as I think they are" In this case you came in here talking shit, and the adjective I used to describe you was in fact quite fitting, as illustrated so wholesomely by your last post. But much like math, English and it's usage is ALSO clearly, not a strong suit of yours.

The truth doesn't have to be nice, it just has to be TRUE. Thank-you for proving that, AGAIN. LMFAO!

Satire requires the reader to be an active participant with sense enough to know that not everything is what it seems. And for the satirically handicapped (such as yourself) satire becomes a taxing, humiliating and downright offensive experience to the point that they (the satirically handicapped) lash out against the creator of said satire.

[lionelhutz]

When I called you a piece of shit it was satirical....

So, it must be you who's lashing out. LOL

[CDeeZ]

Okay now I just feel bad…………










I didn’t realize you are that severely mentally handicapped.

[tamperedchevy]

cdeez, you need to just ignore this lionel thing.

[tamperedchevy]

and lionel.....what the hell are you doin? seriously?(both questions are rhetorical) 4yrs later? someone just wanted to talk about a transmission. stop..just stop.

[CDeeZ]

cdeez, you need to just ignore this lionel thing.

I'm not going to lie to you.......... I get a kick out of getting him so flustered.


and lionel.....what the hell are you doin? seriously?(both questions are rhetorical) 4yrs later? someone just wanted to talk about a transmission. stop..just stop.


Yep, I just thought it was pretty cool that a trans that has had the shit beaten out of it and otherwise abused as long as I have owned it finally had to come apart because of a broken slider key. I'm sure the previous owner(s) were no nicer to it than I was. A transmission that has been in service for 23 years owes nobody anything as far as I'm concerned. I planned on running it till something forced me to take it out and apart. Aside from the broken slider key the only other thing wrong with it was the splines on the mainshaft where 5/6 gear rides are about halfway gone, another common problem with higher mileage units that were probably originally LT1 boxes.

He got really hung up on that bearing a couple days ago. Not my fault he took the bait again. It was pretty hilarious though. It was in fact stained like I said. I soaked it in MEK for several hours and it wiped off. No matter anyways, that F-body unit is so high mileage now I have set it aside to be faceplated when I go through it and build it up for my Chevy II. To replace it I have built a "new" unit by using Corvette internals for the triple double cone synchros and the SSR mainshaft plus all the usual upgrades, solid keys, bronze fork pads, steel 3/4 fork. Also added a -6AN fitting for a pump. I haven't decided how I want to control the pump. The easy thing would be to put it on a switch or wire it into hot on key on source. I had an idea that I could use a hobbs switch to make it come on. Or possibly incorporate an Arduino board to kicK the pump on at a cetain TPS % like say 50% TPS. Another idea, is to have it come on at a certain boost level. Currently running 8 pound springs in the wastegates on my setup.

[1project2many]

Gentlemen....

I'm disappointed in what this thread has become. Disagreement is fine but this is over the top.

CDeeZ, success stories are always good. I've proven the internet wrong myself a few times and I know how tough the crowd can be when trying to tell them that "Everyone" was wrong. When it gets bad you can walk away or ignore the ones you don't want to hear. There's no need to go to where you are now.

lionelhutz, asking valid questions is fine. But recognizing when someone has an emotional stake in their conclusions is even more important. All the readers lose while you are trying to win a fight like this.

This flame war has gone on far too long. Please end it now.

[CDeeZ]

For me, forums are for two principle reasons. To help others learn when and where I can, and to learn myself.

Years ago, me and a handful of other guys were some of the first, if not THE first to be putting T56s in big heavy fullsize trucks. If anyone else was doing it, we certainly were not aware of it. So we were plowing new ground. There was a swap thread first on FSC where I was one of these first few guys to do this T56 swap. Others that come to mind are Alocious, MrPlow,Project88. I think that post is long gone but Alocious reposted it on his website here. Some of the pics are mine:

http://www.gmtruckcentral.com/articles/t56.html


Buying a car with a 6 speed already in it is easy. But to take a bunch of disparate parts and figure out how to make it work, and more importantly how to make it last (in a big heavy truck) is a whole nother level of challenges.

Hard data and numbers are great when available. But sometimes a person's expertise and experience is the better guiding factor. An analogy could be you think you're trying to hit stoich for idle, you know that according to theory, data, and numbers you want to hit 14.7 AFR. However, for whatever reason you might find that a different AFR gives better results. So you end up deviating from what pure raw data and numbers might tell you to do. A hypothetical assumption perhaps?

I figured out that this trans is probably more like 24 years old, not that it matters much between 23 and 24. But the shifter offset lever and the skipshift lever are seperate pieces on this unit which I believe dates this box to ~94. They became one piece around 95 sometime AFAIK.

These are the facts:

A T56 was in service for 24 years before a broken slider key brought it down.

There was no catastrophic failure or any indication that one was imminent, rather, a high mileage unit that could easily be brought back to new by addressing the typical T56 problem areas AND, the things that need dealt with in such a high mileage box like I mentioned.

I am almost done putting together it's replacement, a T56 hybrid I'm building which is utilizing a 50,000 mile Corvette T56 donor for internals, an F body front plate, SSR 32 spline mainshaft and a fluid pump etc. etc.

I will be finished with this newest T56 I'm building soon, and I can't wait to get back to rowing gears, hearing that BOV open up every time I shift, spinning all the way through 4th on demand, and having a blast doing some more stoplight and freeway boost trolling.

[lionelhutz]

Bearing staining is the first stage indicator of an overheated bearing. It doesn't just happen for no reason. This is not my personal opinion, this fact comes directly from the experts at the bearing manufacturing companies. All good bearing manufacturers publish this fact in their failure analysis documents. They will also highly recommend investigating the issue and not just putting the bearing back into service. You can wash it off and re-use it, but you're just putting a bearing that has been taken to the edge of permanent failure back into service without figuring out why it almost failed.

[CDeeZ]

I know what you mean lionel. All I was trying to say is that based upon my experience, I would make a personal judgment call saying "hey this bearing is certainly not brand new any more, but I wouldn't hesitate to keep it in service longer". Tapered roller bearings are pretty damn tough from my experience with them.

It doesn't matter though because that box is shelved for future use in another project. Maybe I will replace the bearings then who knows? Honestly, I probably won't though. I'm not afraid to run it till it breaks because I have the tools, knowledge and skill to fix it when it does. I typically run things as far as I possibly can no matter what anyways. One of my daily beaters is a 97 F150. It's been a great truck. But with literally 350,000 miles on it, it sounds like a metal coffee can full of drywall screws when you start it up on a cold morning. I'll be surprised if it doesn't make it to 500,000 miles!!! My personal "secret" if you will?? I make my own "blend" of oil by using mostly 15w40 diesel oil with a splash of ZDDP additive. OVerkill??? Probably so. But why the hell not?!?

I found this from Timken:
https://www.youtube.com/watch?v=hVuReXrZ8Mg

Pretty cool. Maybe to you, that bearing looked worse than it was, but like I said, In my opinion, and from my experience it was not something I would even worry about. It didn't look like any of the bearings shown in that video. That's for sure!

Like I said though it's irrelevant because for this hybrid T56 I'm building I just dropped in the entire internals from a NON Z06 T56 for the triple/double synchros. It was just easier than way. Plus, that trans only had about ~50K miles on it so that was another reason I chose to do it that way.

I don't want to surround myself with "yes" people and those who think exactly like me. How fucking boring would that be? I respect your difference of opinion/judgement call/perception whatever you want to call it. Please respect mine. We're all on the same team here. Should be anyways. I know what you're saying though. What I've been trying to say for a while though is something like this....... My style is a lot like sloppy mechanics.... If you don't know about this, please google it. His motto is "I'm giving hot rodding back to the people"

For anyone who might not be familiar with sloppy mechanics just check these videos out:

https://www.youtube.com/watch?v=o7HRwRTVX_Y

https://www.youtube.com/watch?v=YWT4JMw2hS8

This ^^^ I love. I spent so much time reading and reading while I was piecing together my S475 LQ4 setup that lives in front of this T56. I copied as much shit from the internet and sloppy as I could because there is really no need to reinvent the wheel. It has paid off. That truck is the fastest car I've ever owned/driven. When I push the pedal down far enough it spins, 1st, 2nd, 3rd, 4th, doesn't matter it just spins. It consistently points the nose towards the ditch on the right hand side. It was enough to make me shit my pants the first time I really uncorked it. But that's my style man, do what you can with what you have, even if it means reusing rusty junk. Most people around here see this truck and probably think "oh look at this shitty farm truck". That really isn't far from the truth, but when I smoke their ass in a clapped out truck with the aerodynamics of a barn door it makes me giggle like a little fucking girl. I haven't found anything on the street that has beat me but I'm sure I will. Or maybe not? It depends on how much I crank up the boost and whether I decide to keep the tires on there that spin because it's fun sliding all over the place or switch to something that will actually hook up. A couple of the local street rats challenged me to a race. I said Sure! Let's race up the twistys to Hennessey and back! (Town north of here). That shuts them right down! They can think for '1320 feet and then that's it brain shuts off.... Those cars would kill me in a drag race. But I would absolutely dominate on a long range bombing run, and be more comfortable with double overdrive, power windows and locks, plush interior and sound deadening, sound system, CUP HOLDERS LOL you get the idea. Everybody around me is stuck in the past in a lot of ways: carbureted big blocks, powerglides, way fucking loose converters etc. etc. That stuff is all cool don't get me wrong, but not many around my part of the world have embraced the advantage(headache) that is EFI and LSx.


Lionel: The factory (Tremec) endplay specs for the T56 is .000" to .002" endplay on the mainshaft, .000" to .002" preload on the countershaft, and .000" to .002" endplay on the countershaft extension.

I have set the main and counter BOTH to a preload of .002" this go around. I will likely do the same for the countershaft extension. To me it makes more sense to preload them to account for the case expansion. And being a tapered roller bearing preload is a good thing IMO. Endplay is not. I set that OTHER T56 up to Tremec specs when I converted it from LTx to LSx. I'm going to experiment with a slight preload all the way around this time. Many guys on LS1tech talk about doing preload on ALL of them.

[CDeeZ]

All good bearing manufacturers publish this fact in their failure analysis documents.


The factory (Tremec) endplay specs for the T56 is .000" to .002" endplay on the mainshaft, .000" to .002" preload on the countershaft, and .000" to .002" endplay on the countershaft extension.




And this is to both of those statements listed above..... And?????? So what???????? Don't take this personal and go ape shit again I'm just saying. I do what works for me. I don't care much about what is written down somewhere or stated. I will investigate it, consider, and ultimately it is still MY decision to make. So what's wrong with having some autonomy in the matter and doing something independent of what is stated or published by someone else? ALL OF THESE QUESTIONS ARE RHETORICAL. Don't freak out.

[CDeeZ]

I found this and thought it an interesting read.

It is a failure analysis from SKF. These are excerpts from the "Limits of acceptability"

Abrasive wear:
"Wear that results in a mirror finish on the bearing components might be acceptable. However, further clean conditions are needed. When wear causes ridges that can be felt with a fingernail or other blunt probes in the running surfaces of the bearing, the bearing should be scrapped."

Corrosion:
"Bearing components with corrosion damage that can be felt with a finger nail should be scrapped. A stain on the surface of the bearing components might be acceptable if it can be removed by polishing with fine abrasive paper."

Vibration corrosion:
" If the damage to the surfaces can be felt with a fingernail, then the bearing should be scrapped. Light vibration markings on the bearing surface might be acceptable if they can be polished away with abrasive paper and/or cannot be felt by a fingernail."

Indentation from debris:
"Over rolled indentation damage is not acceptable if widespread throughout the bearing as shown in the photo. It might be acceptable if only slightly damaged and not present across the entire raceway."

Discoloration:
"Lubrication stains might be acceptable if no other damage is present. Blue discolouration caused by heat is not acceptable on any bearing component."


I think this is interesting. I have never looked into any of this before but I have always used my fingernail to see if it catches on bushings, bearing races etc. as a determinant of whether the part in question needed to be replaced or not. It seems that SKF is reliant on the user of a bearing being smart and independent enough to be able to make a judgement call in the field. This was my approach. The bearing staining that I have witnessed in that other T56 from the pictures had a rusty brown/dark red discoloration. Which, according to this SKF failure analysis document, is "acceptable" provided no other damage is apparent.

[lionelhutz]

SKF really only says it might be OK, which is likely why you quoted acceptable. If you read what I posted, I said the bearing has staining which is the first stage indicating it has experienced overheating and also that means it was taken close to having permanent damage. If it was overheating, then when the overheating continued it would have advanced beyond the first stage. It might be still be Ok, or it might not. If it was a big bearing for a critical application that cost a good chunk of cash then a much closer inspection would be called for. On a cheap bearing, it makes sense simply to replace it and not take the chance on it. It's easy to determine when a bearing is definitely bad, but not always so easy on a worn one that has bad indicator signs but still doesn't show failure damage.

[CDeeZ]

Yeah. It just seems to me that they want the end user to have sense enough to know what they're dealing with more than anything. They're not saying Yes or No one way or another but just "might be acceptable". Which I still take to mean that the end user of the bearing is responsible for being smart enough to make a judgment call. I agree; if there was any doubt just replace it on a cheap bearing. But again, it all comes down to a personal judgement call, for me anyways. Can you post the failure analysis documents indicating bearing staining is a first stage indicating overheating? If so, that will be an interesting contrast to the SKF document as well as the Timken video I posted.

Maybe I have been lucky, but I can't recall a single time I have ever had a tapered roller bearing fail on anything I've ever messed with that uses them. I had a T56 pilot needle bearing explode and wreck an LTx T56 input shaft. I have ONLY run pilot bushings after that. And bronze ones.... I check them with a magnet to be sure they're not iron bushings, that's no bueno for a pilot bushing.

Do you care to weigh in on preloading the bearings a tad bit as opposed to having endplay like I mentioned a ways up? I have found multitudinous posts on LS1Tech where guys are setting them up with preload. Which is directly contrary to what Tremec publishes.... Here are some I found easily.

https://ls1tech.com/forums/manual-transmission/1190043-need-t56-input-shaft-end-play-preload-setting.html

https://ls1tech.com/forums/manual-transmission/1442365-shimming-mainshaft-countershaft.html

https://ls1tech.com/forums/manual-transmission/1638837-t56-countershaft-shimming.html

[lionelhutz]

They always leave it up to the end user. The right wording makes it easier to not get sued.

I don't recall which manufacturer so I'd have to look for it. I've also seen it in online and print documents in industry magazines before.

From what I've seen, taper bearings tend to have a decent life with a fairly wide range of end play, have best life with a little preload and then die quickly with too much preload. In other words, the life of the bearing is the best with a little preload and the life drops off slowly as you move towards too much endplay while it drops off quickly with too much preload.

You can find papers where trucking companies are starting to use specialized equipment to install axle bearings with a preload. It's interesting stuff but basically comes down to them being more reliable when done with precision as opposed to putting the nut tight and then backing it off a little.

I have no idea why the specification is how it is. There are probably good reasons behind it. 0.001" to 0.002" seems like a decent preload target for the sizes of bearing in the transmission. The only reason I could see it not working is if the shaft heats up more than the case and tightens them further, which might be possible on some of the OD gear sets while under significant load. That one bearing is the smallest so it would be the one to watch for issues due to too much preload.

[Xnke]

What's worse, CdeeZ, isn't the bearing staining, it's the surface shear failure in that same photo. Look on the gear teeth at 8 and 9 o'clock, you see those tiny pits on the involute face? That is the material failure. They will only get worse, and there's nothing you can do to fix them. Maybe it's just dirt, but to me, that's the textbook pitting of a surface shear failure.

Same thing happens in a flat tappet cam when you don't have enough EP lube in the oil, or the valve spring pressure is too high, or you're just running much too aggressive a profile on the cam lobe. The lube gets forced out and you get metal-on-metal right there in a tightly focused area, which results in the hard surface literally tearing off the softer core-thus "surface shear" failure. Ways to fix that issue is use a lube with more phosphorus or sulfur, although I think boron compounds are the new hotness in EP additives.

Could also be that the oil was fine, but just breaking down from the same heat that stained those bearing rollers. Do you have more photos of similar detail on the countershaft gears?

[1project2many]

What's worse, CdeeZ, isn't the bearing staining, it's the surface shear failure in that same photo. Look on the gear teeth at 8 and 9 o'clock, you see those tiny pits on the involute face? That is the material failure. They will only get worse, and there's nothing you can do to fix them. Maybe it's just dirt, but to me, that's the textbook pitting of a surface shear failure.

I noticed the same issue. But without knowing the condition of the transmission before installation I didn't want to assume all of the damage was due to towing. If the damage is due to the current application, it seems like the transmission has survived long enough to suggest that it may be worth investing time to improve it's chances.

[CDeeZ]

They always leave it up to the end user. The right wording makes it easier to not get sued.

I don't recall which manufacturer so I'd have to look for it. I've also seen it in online and print documents in industry magazines before.

From what I've seen, taper bearings tend to have a decent life with a fairly wide range of end play, have best life with a little preload and then die quickly with too much preload. In other words, the life of the bearing is the best with a little preload and the life drops off slowly as you move towards too much endplay while it drops off quickly with too much preload.

You can find papers where trucking companies are starting to use specialized equipment to install axle bearings with a preload. It's interesting stuff but basically comes down to them being more reliable when done with precision as opposed to putting the nut tight and then backing it off a little.

I have no idea why the specification is how it is. There are probably good reasons behind it. 0.001" to 0.002" seems like a decent preload target for the sizes of bearing in the transmission. The only reason I could see it not working is if the shaft heats up more than the case and tightens them further, which might be possible on some of the OD gear sets while under significant load. That one bearing is the smallest so it would be the one to watch for issues due to too much preload.

I found this talking about how preload is gaining favor over endplay:
https://www.vehicleservicepros.com/vehicles/under-vehicle-trailer-towing/tire-wheel/article/10712957/why-preload-settings-on-wheel-end-bearings-are-favored-over-endplay-settings

As far as the spec on setting endplay or preload as provided by Tremec I'm going to quote the guy from one of the posts I linked:

"Setting up a transmission that has tapered roller bearings with end-play/no-preload only accomplishes one thing, and that is bearing wear/noise a few years down the road when the clearences open up and there is too much play...

Great for rebuild shops and dealerships as they get more work. Sucks for the consumer... "

I couldn't agree more. It seems best to me to set up a slight preload or a very MINUSCULE endplay. Just because some engineer type at Tremec somewhere decided on that spec doesn't mean much to me. I will look at their spec and still ultimately decide what I want to do. Which if you look around on LS1tech there are hoards of people disregarding the Tremec spec in favor of tighter shimming like I mentioned.

Good point about the smaller bearing being the one to watch out for. 85MikeTPI wrote that article on building a T56 hybrid and has many posts on LS1tech pertaining specifically to the T56 which seem pretty credible to me. I'm going with the specs he used which are listed in that 3rd post I linked.... Which in the case of the counter-extension is .000 - .001 endplay.




What's worse, CdeeZ, isn't the bearing staining, it's the surface shear failure in that same photo. Look on the gear teeth at 8 and 9 o'clock, you see those tiny pits on the involute face? That is the material failure. They will only get worse, and there's nothing you can do to fix them. Maybe it's just dirt, but to me, that's the textbook pitting of a surface shear failure.

Same thing happens in a flat tappet cam when you don't have enough EP lube in the oil, or the valve spring pressure is too high, or you're just running much too aggressive a profile on the cam lobe. The lube gets forced out and you get metal-on-metal right there in a tightly focused area, which results in the hard surface literally tearing off the softer core-thus "surface shear" failure. Ways to fix that issue is use a lube with more phosphorus or sulfur, although I think boron compounds are the new hotness in EP additives.

Could also be that the oil was fine, but just breaking down from the same heat that stained those bearing rollers. Do you have more photos of similar detail on the countershaft gears?

If you're talking about some of the stuff circled in red it was dust, shop rag lint etc. Also, I'm taking these pics with a new to me camera, it's on my Note 8 phone so I'm still getting used to how to operate it to depict things in the most clear manner. I'll have to revisit that when I build up that T56 for a future project. I will likely send it to Liberty to be faceplated so I'll just have them do whatever else needed at that time.

Excellent point about flat tappets. Everything I have that is flat tappets gets an extra dose of ZDDP for that reason.


I noticed the same issue. But without knowing the condition of the transmission before installation I didn't want to assume all of the damage was due to towing. If the damage is due to the current application, it seems like the transmission has survived long enough to suggest that it may be worth investing time to improve it's chances.

The hybrid T56 that is going in place of the one that was pictured a few posts back will have a fluid pump which will help the trans in any conditions be it towing, hard acceleration etc. We tig welded a -6 AN bung in the case exactly where the TR6060 has one. Eventually this will be plumbed into a pump and possibly also a cooler. I'm hoping I can control it with a TPS % or boost threshold plus a manual override toggle switch for whenever I want to have it on anyways.


Also, the specs from the Tremec service manual for endplay on the counterextension that I posted in post #57 are in contrast to this one I'm posting now. I believe this one is the correct spec (as per Tremec) but I'm ignoring them anyways hahaha. Interestingly, they both came from the same T56 service manual so there appears to be a discrepancy there. Notice the title from the service manual "Shimmin Procedures"..... Guess they couldn't be bothered to put a g on the end LOL.

[1project2many]

Notice the title from the service manual "Shimmin Procedures"..... Guess they couldn't be bothered to put a g on the end LOL.

Engineers are constantly working to save the company a dollar here or there. So what if one of the technical writers decided to save a "g" on every manual?

[CDeeZ]

Engineers are constantly working to save the company a dollar here or there. So what if one of the technical writers decided to save a "g" on every manual?

:laugh: Reminds me of one of my college roommates. He is a mechanical engineer. Every time I introduce him I say: "this is Daniel, he's an engineer............... but we like him anyways" hahaha.

I think the problem with the technical writers is usually that they are engineers. They need to be someone with a masters degree in English or otherwise possessing a strong command of the language in order to clearly convey things.

[1project2many]

And yes, the areas that looked like damage to the gear are the areas you've circled in red. I guess it's not cavites, just linty-fresh tooth wash.

[CDeeZ]

Well I got the "new" frankenstein hybrid T56 back together and drove around last night.

Some observations:

Shift quality is absolutely amazing with everything all freshened up inside (bronze pads, solid keys, steel 3/4 fork, Corvette synchros). I have a MGW shifter that should be here towards the end of the week to make it even better.

The tighter shimming I elected to go with has apparently paid off, this trans is virtually silent. It doesn't even make the typical and common T56 neutral rollover rattle.

I forsee no problems whatsoever with beating the shit out of this T56 for a long long time, AND doing truck duties with it when needed, towing etc.

I am working on a walkaround rambletron style video of the truck so everyone can see what this is all about.



Lionel: Are you going to post the failure analysis documents supporting your claims to contrast with my own as well as the two I posted from SKF and Timken?

[CDeeZ]

Okay........ I know everyone has just been on the edge of their seat to see what all the fuss is about............

Well here it is....... The turbocharged T56 towtruck walkaround video. Rambletron style.


https://www.youtube.com/watch?v=ceq_kx6i32Q

[Hog]

Nice vid, do you have any driving vids? I like the acceleration vids when it was naturally aspirated. Gearing makes all the difference with these types of builds, both for durability, drivebility, fun factor. The transmissions are almost useless in heavy applications with stock 1/2 ton gearing with the high 2.66:1 1st and high 0.50:1 OD. A nice rear gear like those 4.88's make it all useable and fun.

Very nice!

peace
Hog

[CDeeZ]

Thanks Hog!

I intend to get some driving vids up soon!! Between work and other projects, plus having to build up this T56 frankenstein hybrid I've been pretty busy. Those older acceleration videos are when it was still a SBC TBI!! It was fun even then with the T56 and only ~300FWHP! The LQ4 makes about 330HP STOCK plus 8 pounds of boost which means this old OBS really smashes around.

You are spot on about gearing, it is very critical here. The deep ratios of the T56 plus the tall truck tires necessitate numerically high ring and pinion ratios. When I first put the T56 in years ago behind the SBC that USED to be in there, I drove around for a while with the stock 3.08 gears...... That meant that you had to slip the clutch big time to get going in 1st and 6th, well that gear was useless with the 3.08s...... The 4.88s are a perfect match...... Now that it is boosted, something a little lower (numerically) could also be good, like maybe 4.11 or so....

I can't tell you how many times I've had people either in shock and awe or straight up try to argue with me about 4.88 and their streetability...... Pulls like a freight train/spins the tires through 4th, and if you stick it in 6th gear you are turning 1978 RPM @ 70MPH....... VERY streetable with the 4.88s.... But then you know how that goes. Just because something is written down on paper somewhere, or it makes sense in a CAD program to an engineer; none of that really matters in the real world when you're talking about a home-built hot rod.

Did you used to post on other forums ? I seem to recall your handle.

[CDeeZ]

MGW shifter showed up. Damn it looks like a nice piece.


https://i.imgur.com/UEENyfo.jpg


https://i.imgur.com/uxaUd2B.jpg


https://i.imgur.com/WsMalZj.jpg

[CDeeZ]

Getting ready to tear the timing cover off and ditch the stock cam in favor of one significantly larger. I'd estimate a 50HP gain N/A and somewhere in the range of 100HP in my case given the turbocharger.