2022 Silverado 2500HD with the dreaded 6 speed shudder

CamGTP · March 25

The 6L90e is a heavier transmission, they do have different upgraded hard parts and more clutches/steels than the 6L80e. They function the same way but the 6L90e is different on the inside. Both transmissions are controlled with a pretty similar tuning structure. Shift times, pressures, converter settings are of course going to be different because half tons and 3/4-1 Ton trucks have different needs.

Jettech1 · March 25

25 minutes ago, CamGTP said:

The 6L90e is a heavier transmission, they do have different upgraded hard parts and more clutches/steels than the 6L80e. They function the same way but the 6L90e is different on the inside. Both transmissions are controlled with a pretty similar tuning structure. Shift times, pressures, converter settings are of course going to be different because half tons and 3/4-1 Ton trucks have different needs.

What I love about the 6L90 is, it's a beast. Way over built. Used in racing applications and HD trucks. It's way simpler than the 10L1000. It just works. And keeps on working.

carkhz316 · March 25

9 hours ago, Jettech1 said:

Sorry man, but that's where I need to call BS. I love conversation but there are huge differences mechanically between the 6L80 and 90. And the TC is different as well. Tell me I'm wrong.

I don't know what you're getting at. You mention not knowing much about the transmission and wanting to learn, yet then counter my points despite evidence.

The torque converters are the same. There are certain applications of 1-ton trucks and vans utilizing a 6-bolt mounting vs the 3 bolt, but they're otherwise physically the same.

Regarding the transmissions themselves: "nearly" identical is a slight exaggeration. They share 'only' 75% of their internal parts

https://www.novak-adapt.com/knowledge/transmissions/automatic/6l80.html

https://gearstar.com/blog/6l80-vs-6l90-devils-in-the-details/

Key differences of the 6L90 include: A longer case, different output shaft, an additional clutch friction in the clutch packs, and 6-pinion planetaries. Most of the remaining hard parts are the same and interchangeable.

Rogue Leader · March 25

Wow, this seems to have exploded.

While I don't know for sure I can infer in my case that the leaky trans cooler combined with negligence may have been the issue.

Backstory, my truck was a fleet vehicle for Southern Tire Mart which also owns some dealerships in the Mississippi area (Pine Belt Auto group, which is where I got it). The truck has the 5th wheel package and I believe was used to tow a trailer for tire service. I do have the full maintenance history on the truck, it was maintained at the dealer, and is otherwise in surprisingly perfect condition considering its use. Anyway they did do a whole bunch of maintenance before selling it to me, and I got a good deal.

The servicing dealer after fixing the leak told me it had probably been leaking for a while as the transmission was quite low on fluid. The other thing is while it did shudder it basically drove fine. Went into gear, reverse, etc, shifted up and down, it was just noisy. So I can imagine that some fleet driver was just like whatever about it and drove it around like that.

So yeah based on that I'd assume it was the low fluid condition, which was ignored and continued to use for towing that caused the damage. I have read some nightmare stories about the 6L90, but then others that say its bulletproof, so its hard to know for sure. I kinda want to add 2 bottles of Lubegard to it which supposedly helps protect it, but getting 20oz of fluid out of the transmission and this in its place without causing a disaster seems like an impossible task with no dipstick. Considering its under warranty I don't want to f with it.

Edited March 25 by Rogue Leader