Towing with T56

[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-tr...d-setting.html

https://ls1tech.com/forums/manual-tr...ntershaft.html

https://ls1tech.com/forums/manual-tr...-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?