302 cubes for Suburbia

[1project2many]

I did check for valve spring bind. And there was none. Except... there was bind.

Turns out that my machinist friend and myself both failed to notice the damper springs had to be removed. The L31 valve guide is machined so it closely fits the ID of the stock springs in order to damp oscillations. Well, the ID of these springs matched the stock L31 parts and the OD of the damper was the same as the OD of the guide. Can't put two pieces of matter in the same space at the same time. But because it was inside the primary spring I never noticed it when I was checking the primary coils for contact on the vehicle. It was very good to find this, although it would have been much better to find it before I did damage. So I'm out the cost of a set of GM performance head gaskets (about $36) and a ton of time. Engine starts and runs.

Right now I'm sitting and waiting for silicone to cure at the timing cover. The adapter I built to run the Vortec plastic cover spaced the cover forward about 1/16 inch roughly. This put a little extra pressure on the lower portion where the pan gasket sits. All the parts sealed tightly. But as the engine warmed up the cheap plastic cover decided to change shape slightly and conform to the pan which left a small gap at the pan/block/cover intersection. No problem. We've got some really good sealer here so I filled 'er up. In a few minutes I'll fire it back up, do a crank relearn, check the distributor / cam sensor position, and I'm outta here.

[EagleMark]

Well I'm glad that's over!

[1project2many]

Drives ok so far. Mostly highway. No surprise that off the line pull isn't strong but on the highway there's plenty of go. Had to decrease cranking PW to match smaller engine displacement to help startup. Also have a slight hunting idle when warm in gear, possibly due to reduced loading from higher stall converter. Reduced spark corrections for idle speed by .9 across the board to see if this helps. Fuel economy seems reasonable by seat of the pants but I haven't done enough driving to get real numbers. And, the engine's still brand new so it will change some anyway.

[1project2many]

As I have time I play with the truck. It's not often, as my handle implies. Warm restart is a beech. I've tried looking at 305 cals for hints as to what GM did for the smaller engines but there are enough differences here that a simple comparison doesn't reveal enough answers.

I really need to get better scantool data. The free software I'm using in my laptop tries to display basic data but what I get is not enough to tune with. I don't even have IPW. I can swap to the 0411 but I get stubborn about things sometimes and I'm feeling like fighting with this one for a bit longer. So I guess the next step is to get the shop's Modis involved and see what's available in the "official" datastream. If some of the data I'm looking for is there I'm going to have to see about implementing it in the free software.

Lots to do, lots to do. And we're already a week into June!

[Hog]

Nice to see that you built the L99 based 302. With teh L31 heads/ and Ramjet 350/HT383 cam on only 302 cubes, it should make some decent power, and at a higher rpm.

How does it feel compared to the 350? Does te power peaky at all?

If you had to do it all over again, would you simply do a 305?

Interesting manifold, I wish you were close so you could try my my Merc cross ram intake on it.



On your intake, I have to wonder if the single 75mm t-body on your 4 hole intake is playing havoc with airflow? I would find it hard not to machine that out to match the 75mm truck t-body.

Are you running the stock 1 7/8" L31 1/2 ton headpipes?

1/2 ton and 3/4 Vortec 350 headpipes side by side


I would love to see a chassis dyno report on this beast once you get it all smoothed over.

PS I might be tempted to dump a stock L30 305 calibration in it obviously corrected for the correct IFR of your injectors. What are your flowing and at what pressure? What are you using for a fuel pressure with the vacuum refernce disconnected?

Good work.

peace
Hog

[1project2many]

Right now I'm still using the stock L31 intake. I chose to install it during the initial engine install to save time and my plans are to install the dual plane in the future.

305 calibrations are almost always a poor match for 4" bore engines. For some reason the 305 is much more detonation prone. The L30 is better than the L03 but you can still see the changes both in the spark tables and the knock retard when compared to the L31. Between the longer rods, slightly lower compression, and different cam this engine is definitely in need of it's own spark map.

As I dial in the spark map I find the engine like to launch off the line, lose some acceleration in the middle, and then pull again near top end. That's no surprise as dyno software predicted that behavior. I lose some of the advantage of the long runner intake because of the loose converter but it's still usable. Next weekend I'm going to be towing a trailer with a compact diesel tractor through a 150 mile trip so I'll have a better idea of how it feels under load. Ultimately I want it set up with the dual plane and any impressions with the stock intake are just for perspective.

I am running stock exhaust after the headers. I've looked at changing them but unlike OEM, the aftermarket stock replacement exhaust systems I've looked show no difference between 1/2 and 3/4 ton models. I have plans to get down to the exhaust shop and have a new system built front to back but that might not happen until August.

As to running a 305, no. The L31 is so common that I'd buy one used before installing the 305. I built the 302 years ago to do it, and because I thought it might be a good choice for an S10 Blazer. I've been dying to use it since and when I replaced the last Blazer with the Suburban, I found an opportunity to try it. If I were to build a long stroke, small bore engine I'd probably throw a 400 crank into a 350 block. IIRC that works out to about 338 cubes and it might make an interesting torqu engine with very good emissions.

[Hog]

Right now I'm still using the stock L31 intake. I chose to install it during the initial engine install to save time and my plans are to install the dual plane in the future.

305 calibrations are almost always a poor match for 4" bore engines. For some reason the 305 is much more detonation prone. The L30 is better than the L03 but you can still see the changes both in the spark tables and the knock retard when compared to the L31. Between the longer rods, slightly lower compression, and different cam this engine is definitely in need of it's own spark map.

As I dial in the spark map I find the engine like to launch off the line, lose some acceleration in the middle, and then pull again near top end. That's no surprise as dyno software predicted that behavior. I lose some of the advantage of the long runner intake because of the loose converter but it's still usable. Next weekend I'm going to be towing a trailer with a compact diesel tractor through a 150 mile trip so I'll have a better idea of how it feels under load. Ultimately I want it set up with the dual plane and any impressions with the stock intake are just for perspective.

I am running stock exhaust after the headers. I've looked at changing them but unlike OEM, the aftermarket stock replacement exhaust systems I've looked show no difference between 1/2 and 3/4 ton models. I have plans to get down to the exhaust shop and have a new system built front to back but that might not happen until August.

As to running a 305, no. The L31 is so common that I'd buy one used before installing the 305. I built the 302 years ago to do it, and because I thought it might be a good choice for an S10 Blazer. I've been dying to use it since and when I replaced the last Blazer with the Suburban, I found an opportunity to try it. If I were to build a long stroke, small bore engine I'd probably throw a 400 crank into a 350 block. IIRC that works out to about 338 cubes and it might make an interesting torqu engine with very good emissions.

400 crank into a 350 block is 377, 400 crank into a 305 is a 334 again depending on overbore.

I understand now why you chose a 302.

There are many after market replacements that differentiate between the 1/2 ton and 3/4 ton exhausts. Magnaflow, Walker and Catco are just 3.

Magnaflow 1/2 ton Vortec L31 350


Magnaflow 3/4 L31 front and back







catco front and back for 3/4 ton L31



On my stock longblock L31, headers/mild 87 octane tune changing only the PE fuel multiplier and exhaust dropped 1/4 miles times just under a second. Felt like I dropped a 383 under the hood. And that was with the same stock intake you are using. When I went to its match dimensionally anyways wit the Merc intake, I noticed better over 4500rpm breathing with small torque increases off idle and at low rpm.


All else equal the small bore 305 should be MORE detonation resistant than the larger 4" bore. I might be tempted to work from an L30 calibration.

Good work on your build. It muist be nice to finally see some fruits of your labours.

peace
Hog

[1project2many]

There are many after market replacements that differentiate between the 1/2 ton and 3/4 ton exhausts. Magnaflow, Walker and Catco are just 3.

I'll look again at Walker. Maybe I just missed it. Local exhaust guy is Magnaflow dealer so maybe I can get a good price on an expensive brand.

All else equal the small bore 305 should be MORE detonation resistant than the larger 4" bore. I might be tempted to work from an L30 calibration.

I've never really investigated the 305's issues so I can't tell you why it's more likely to knock. It would seem like head design is the key. The L30 represented a great chance to fix any problems inherent in the older heads yet the tuning tables indicate there are still problems.

Main spark table, knock attack, and knock retard rate comparisons are below. Yes, there's a bit more spark advance on the bottom end but at the top it's a whole different picture. Not only is timing lower on the smaller bore, but GM is really quick to remove advance if knock occurs and slow to return it. This is typical of the 305 although it's less pronounced here than older engines.

[ony]

one of the main spark tables is off in 2 aereas by 20-23 degrezz in the upper part of the table.

[Hog]

one of the main spark tables is off in 2 aereas by 20-23 degrezz in the upper part of the table.

That is the actual spark timing table, its the differnce in timing between teh 2 calibrations he is comparing. If you notice, it states COMPARE ON.

This is a stock L30 timing table
0rpm 400rpm 800rpm 1200rpm 1600rpm 2200rpm 2600rpm 3000rpm 3400rpm 3800rpm 4200rpm--5600-6000rpm
20.0 20.0 20.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 26.0 15 kpa
20.0 20.0 20.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 26.020kpa
25.0 25.0 25.0 30.0 30.0 30.0 10.0 10.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 26.0 30kpa
25.0 25.0 30.0 35.0 35.0 35.0 10.0 10.0 30.0 30.0 30.0 29.0 27.0 27.0 27.0 27.0 35kpa
25.0 25.0 29.0 33.0 34.0 34.0 33.0 33.0 33.0 33.0 33.0 31.0 29.0 29.0 29.0 29.0
22.0 22.0 28.0 31.0 34.0 34.0 34.0 34.0 35.0 35.0 34.0 32.0 30.0 30.0 30.0 30.0
22.0 22.0 26.0 29.0 33.0 33.0 34.0 34.0 36.0 36.0 35.0 34.0 32.0 32.0 32.0 32.0
20.0 20.0 24.0 28.0 32.0 32.0 34.0 34.0 35.0 35.0 35.0 34.0 32.0 32.0 32.0 32.0
18.0 18.0 20.0 26.0 30.0 32.0 33.0 33.0 34.0 34.0 34.0 32.0 30.0 30.0 30.0 30.0
17.0 17.0 17.0 20.0 24.0 27.0 30.0 32.0 32.0 32.0 31.0 27.0 25.0 25.0 25.0 25.0
11.0 11.0 14.0 17.0 22.0 25.0 28.0 31.0 31.0 30.0 28.0 25.0 23.0 23.0 23.0 23.0
7.0 7.0 11.0 14.0 19.0 22.0 26.0 27.0 28.0 27.0 24.0 23.0 20.0 20.0 20.0 20.0
4.0 4.0 7.0 12.0 17.0 20.0 25.0 26.0 26.0 25.0 22.0 21.0 19.0 19.0 19.0 19.0
2.0 2.0 4.0 9.0 14.0 18.0 23.0 23.0 24.0 23.0 20.0 19.5 18.0 18.0 18.0 18.0
-1.0 -1.0 1.0 8.0 12.0 16.0 21.0 21.5 22.0 21.0 19.0 18.0 16.0 16.0 16.0 16.0
-3.0 -3.0 -2.0 5.0 10.0 14.0 19.0 19.5 19.5 19.0 18.0 17.0 15.0 15.0 15.0 15.0
-4.0 -4.0 -2.0 4.0 10.0 14.0 18.0 19.0 19.0 19.0 17.0 17.0 15.0 15.0 15.0 15.0 95kpa
-4.0 -4.0 -2.0 2.0 8.0 13.5 16.0 18.0 19.0 19.0 16.0 16.0 15.0 15.0 15.0 15.0 100kpa
-4.0 -4.0 -2.0 2.0 8.0 13.0 16.0 18.0 19.0 19.0 16.0 15.0 15.0 15.0 15.0 15.0 105kpa

Stock 4.3 265 L99
18.0 18.0 18.0 18.0 18.0 19.0 17.0 15.0 12.0 9.0 6.0 3.0 2.0 2.0 2.0 2.0 400 rpm
22.0 25.0 26.0 24.0 22.0 21.0 19.0 23.0 17.0 15.0 11.0 6.0 6.0 6.0 6.0 6.0 600 rpm
26.0 28.5 29.5 26.0 23.0 21.5 21.0 25.0 22.0 19.0 15.0 12.0 12.0 15.0 15.0 15.0 800
29.0 39.5 39.5 39.5 34.0 27.0 27.0 32.0 26.0 24.0 19.0 16.0 14.0 15.0 15.0 15.0 1000
31.0 33.0 32.5 36.0 34.0 33.0 30.0 34.0 30.0 27.0 20.0 19.0 14.0 15.0 15.0 15.0 1200
33.0 35.0 35.0 37.0 35.0 34.0 34.0 37.0 32.0 30.0 26.0 22.0 19.0 19.0 16.0 16.0 1400
35.0 38.0 38.0 38.0 37.0 35.5 36.0 40.0 36.0 33.0 30.0 26.0 24.0 20.0 19.0 19.0 1600
36.0 39.0 40.0 38.5 37.0 36.5 36.5 43.0 37.0 34.0 33.0 30.0 25.0 23.0 16.0 21.0 1800
37.0 40.0 39.5 36.5 34.5 33.5 37.0 43.0 40.0 36.0 34.0 32.0 29.0 25.0 24.0 23.0 2000
37.0 40.0 40.0 38.0 36.5 35.0 37.0 43.0 40.0 38.0 35.0 33.0 30.0 28.0 25.0 23.0 2200
35.0 40.0 40.0 40.0 40.0 40.0 40.0 44.0 40.0 37.0 36.0 35.0 32.0 30.0 27.0 24.0 2400
35.0 40.0 40.0 40.0 40.0 40.0 40.0 44.0 42.0 40.0 39.0 37.0 35.0 33.0 30.0 27.0 2800
35.0 40.0 40.0 40.0 40.0 40.0 40.0 45.0 43.0 42.0 40.0 37.0 36.0 35.0 32.0 30.0 3200
35.0 35.0 40.0 40.0 40.0 40.0 40.0 45.0 44.0 43.0 40.0 38.0 37.0 36.0 34.0 33.0 3600
40.0 40.0 40.0 40.0 40.0 40.0 40.0 45.0 44.0 43.0 41.0 38.0 37.0 36.0 35.0 34.0 4000
40.0 40.0 40.0 40.0 40.0 40.0 40.0 45.0 44.0 43.0 41.0 39.0 38.0 36.0 35.0 34.0 4500rpm
35.0 40.0 40.0 40.0 40.0 40.0 40.0 45.0 44.0 43.0 41.0 39.0 38.0 37.0 36.0 35.0 5000rpm
40.0 40.0 40.0 40.0 40.0 40.0 40.0 44.0 43.0 43.0 41.0 39.0 37.0 36.0 35.0 35.0 5500rpm
35.0 40.0 40.0 40.0 40.0 40.0 40.0 43.0 42.0 41.0 39.0 38.0 38.0 38.0 34.0 34.0 6000rpm
35.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 36.0 36.0 6500rpm
32.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 38.0 30.0 30.0 28.0 28.0 28.0 7000 rpm

Stock L31 350
20.0 23.0 23.0 25.0 26.0 27.0 28.0 29.0 29.0 29.0 29.0 29.0 29.0 29.0 29.0 29.0 15
20.0 23.0 23.0 25.0 27.0 28.0 29.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 20kpa
20.0 23.0 23.0 26.0 27.0 29.0 30.0 32.0 32.0 32.0 32.0 32.0 32.0 32.0 32.0 32.0 25kpa
20.0 23.0 23.0 26.0 28.0 30.0 32.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0
20.0 23.0 23.0 27.0 29.0 32.0 34.0 36.0 35.0 35.0 35.0 34.0 34.0 34.0 34.0 34.0
20.0 23.0 23.0 28.0 32.0 34.0 36.0 36.0 36.0 36.0 35.0 34.0 34.0 34.0 34.0 34.0
20.0 21.0 23.0 28.0 32.0 34.0 35.0 36.0 36.0 36.0 35.0 34.0 34.0 34.0 34.0 34.0
18.0 18.0 21.0 28.0 32.0 33.0 34.0 35.0 36.0 36.0 35.0 34.0 34.0 34.0 34.0 34.0
14.0 14.0 19.0 26.0 30.0 32.0 33.5 34.5 35.0 35.0 34.0 33.0 33.0 33.0 33.0 33.0
12.0 12.0 16.0 24.0 28.0 31.0 33.0 34.0 34.0 34.0 33.0 32.0 32.0 32.0 32.0 32.0
11.0 11.0 14.0 21.0 26.0 29.0 31.0 32.5 33.0 33.0 33.0 32.0 31.0 31.0 31.0 31.0
9.0 9.0 11.0 18.0 23.0 27.0 29.0 31.0 32.0 32.0 32.0 31.0 30.0 30.0 30.0 30.0
7.0 7.0 9.0 15.0 20.0 25.0 28.0 30.0 31.5 31.5 30.0 29.5 28.0 28.0 28.0 28.0
5.0 5.0 7.0 13.0 17.0 23.0 27.0 29.0 29.0 29.0 28.0 28.0 26.0 26.0 26.0 26.0
2.0 2.0 5.0 11.0 15.5 21.5 25.0 27.0 27.0 26.0 25.0 25.0 24.5 24.5 24.5 24.5
0.0 0.0 2.0 8.0 14.0 20.0 23.0 25.0 25.0 24.0 23.0 23.0 23.0 23.0 23.0 23.0
-1.0 -1.0 0.0 6.5 12.0 18.0 22.0 24.0 24.0 23.0 22.0 22.0 22.0 22.0 22.0 22.0
-2.0 -2.0 -1.0 5.0 11.0 16.0 20.0 22.0 22.0 21.0 20.0 20.0 20.0 20.0 20.0 20.0 100kpa
-2.0 -2.0 -1.0 4.0 10.0 15.0 19.0 21.0 21.0 20.0 19.0 19.0 19.0 19.0 19.0 19.0 105kpa

[ony]

at 25-30 kpa -2400-2800 it shows a lot different than the rest of the table, could make for knocks in them cells.

[1project2many]

at 25-30 kpa -2400-2800 it shows a lot different than the rest of the table, could make for knocks in them cells.

It's not so uncommon to see GM throw a bunch of advance at an engine after a certain MAP and RPM. But the telltale is that spark advance begins to drop rapidly as rpm increases. For the L30 GM pulls 4-5 degrees along a given MAP range as RPM increases while the L31 sees only a degree or two at most.

What's even more interesting for comparison is the L99 table. Same bore as L30 but with shorter stroke, longer rod, and reverse flow cooling there's an additional 10 degrees advance at WOT.

The 305 just seems to have issues with advance.

[Fast355]

It's not so uncommon to see GM throw a bunch of advance at an engine after a certain MAP and RPM. But the telltale is that spark advance begins to drop rapidly as rpm increases. For the L30 GM pulls 4-5 degrees along a given MAP range as RPM increases while the L31 sees only a degree or two at most.

What's even more interesting for comparison is the L99 table. Same bore as L30 but with shorter stroke, longer rod, and reverse flow cooling there's an additional 10 degrees advance at WOT.

The 305 just seems to have issues with advance.

Not sure where you are getting all that WRONG SA info on a 305. Keep in mind the L99 was in a car that is lighter and more aerodynamic than the trucks and vans the L30 was put into. The mechanical engine fan alone tends to make the engines more SA sensitive in hot weather as it puts a heavy load on the engine in hot weather. The L99 also has longer rods and a better rod/stroke ratio that makes it less sensitive to detonation under heavy load.

The 305 is not spark advance sensitive, just does not need as much advance as a 350 with its smaller bore the flame front travels more quickly across its smaller area. If anything the 305 is more detonation resistive than the 350. I ran 10.8:1 compression and 230 psi static compression with the old iron 601' casting 305 heads on 93 octane pump gas with a carb and ran 34* total advance doing it.

[1project2many]

Not sure where you are getting all that WRONG SA info on a 305.

The table I've posted is a comparison of stock tables taken directly from GM calibrations. Why do you say it's wrong?

The 305 is not spark advance sensitive, just does not need as much advance as a 350 with its smaller bore the flame front travels more quickly across its smaller area.

Based on experience and backed by what I've seen come out of GM engineering, I disagree fully with your statement. I've been working on 305 equipped vehicles since the '70s. Stock 305's have always had a greater tendency for spark knock. In the '80s, the only GM truck to receive knock control without a fully computerized ignition system was 305 equipped. That wasn't just an experiment to see if it would work. I know what happens when you disable or remove that system. Look through cals matching year for year, 350 to 305, you'll see consistent indications in the form of more aggressive knock retard, less aggressive restore rates, and timing tables that favor less advance on top end. It is not because the 305 needs less advance to create peak pressure at the same time as the 350. Based on the number of degrees difference, the amount of time involved is too great.

Keep in mind the L99 was in a car that is lighter and more aerodynamic than the trucks and vans the L30 was put into. The mechanical engine fan alone tends to make the engines more SA sensitive in hot weather as it puts a heavy load on the engine in hot weather. The L99 also has longer rods and a better rod/stroke ratio that makes it less sensitive to detonation under heavy load.

I am fully aware of the stock configuration of the L99. Which is why I said the stock spark tables make an interesting comparison. And while I agree that a mechanical fan puts more load on an engine, I think it would be naive to say this factor is more important in the L99 timing tables than reverse flow cooling. Cooler heads inhibit combustion rates and the reverse flow engines run substantially cooler heads than standard flow engines.

If anything the 305 is more detonation resistive than the 350. I ran 10.8:1 compression and 230 psi static compression with the old iron 601' casting 305 heads on 93 octane pump gas with a carb and ran 34* total advance doing it.

I have experience tuning. Personally I built and ran a 10.8:1 350 on 87 octane fuel with a manual transmission and a tunnel ram style marine intake on iron heads. That engine was in the 400 horse range. I own a Pontiac Turbo Sunbird 2.0 running 17 psi boost on the stock turbo and fuel system and it hasn't launched the headgasket. That's a tough feat to accomplish with that engine even with upgraded parts. Mine's tuned for 89 octane and I've got a *lot* of time into the cal. I ran a 2.2L engine with 9.4:1 and nearly 8 lbs boost. The engine is stock with the addition of a very small turbo and no intercooling. It was a huge challenge to tune between the wide range of intake temps and the way too large TBI injectors in the PFI intake but the point was to prove it could be done. It made fair power, and the engine didn't blow up as many had predicted. And to make it fun I kept it on 87 octane. I pulled the engine, still running, when I sent the car to the junkyard for rust and saved it for future use. I also have a 302 powered '57 Chevy pickup with Crossfire injection. First installed in '92, I used a 305 ecm from an '83 Firebird. I moved on to a 7747 in '99, and now use a 7427. I have retuned it with each ecm change and have plenty of hours working with the spark tables in that engine as well. For perspective, that engine uses 601 castings and 1.84" valves.

Are you emotionally invested in defending the 305? I'm not discussing (or dissing) it's worth as a potential powerplant. Hog suggested using stock 305 spark tables as a starting point for my 302. I do not believe those tables are the best starting point and I've indicated why.

[1project2many]

Well, the truck made the trip successfully. I'm guessing I was pulling about 4k lbs between the tractor, trailer, and a bunch of "stuff" I pulled out of an old garage. I know that's not a large load but it's probably typical of what I'll be hauling. Overall I'm satisfied that this truck will work out although if I was crossing the Rockies or maybe even towing on the high plains the current combination probably wouldn't make me happy.

There were a couple of larger hills on this trip and at least twice I spent a significant time at WOT on the way home. Dyno software predicted the engine would feel flat around 2500 with the stock intake and boy, does it. At 65 mph I'm right in the middle of that flat spot. The combination of 3.42 gears with the current intake keeps the trans busy which means I've got more work to do nailing the shift tables. I'm going to see if there's a tow/haul or economy switch that will fit right into the dash to make use of dual shift patterns. 3.73 gears would be nice but I'm not likely to go that far. I was towing the entire trip of 335 miles which meant no OD. Empty trailer one way, loaded trailer the other, lots of hills in the middle so I was surprised to see 12 mpg when I calculated the fuel economy. Not that it's engine related, but I'm going to be replacing the gear oil with full synthetic. The diff gets warm when towing and the airflow around the truck carries the smell of hot gear oil right into the passenger area.

So subsequent work will be:
install large trans cooler (didn't have time to install during engine adventures)
service differential with synthetic fluid
Tow / haul button
Adjust shift tables for faster TCC unlock and quicker downshifts, and to hold downshift longer
hot restart parameters still need adjustment
-->Fix A/C!!!<---