Transmission Troubles

RTSGS57 · September 24, 2019

Was wondering if anyone is having this problem. I have a new 2019 2500HD with a 6.0 gas engine and the 6 speed 6L90 transmission. When I'm accelerating at a modest pace, the vehicle surges and shudders. Took it to the dealer and after they drove it they showed me a service bulletin describing the problem. GM said it's normal. They said the transmission flush is for the 8 speed tranny on the 1/2 ton truck. Not sure what to do here. Anyone have advice or similar experience with the 6L90 transmission?

GTBensley · September 26, 2019

I think a few have had similar issues and it ended up being to torque converter. I wouldn't settle for normal, mine doesnt do it.

gearheadesw · September 27, 2019

There’s another thread around here somewhere, lots of people have had that problem, including me on my ‘16 gasser 6 speed. Light to moderate throttle, surging, not tremendous, but noticeable, my 17 with the same set up doesn’t surge.

AbzDad · September 27, 2019

Mine does it. The dealership first thought it was the torque converter or the transmission slipping, then they said it wasn't because they couldn't get the TC to fail in tests. Then they thought it had something to do with the AC, which really didn't make much sense...but again they couldn't reproduce it. They said to keep driving it and if it gets worse to call them back.

I have tried new plugs/wires, used 93 octane gas, fuel injector cleaner and cleaned the throttle body. It still shakes/shutters under light throttle, most notably under light load (going up a small hill or light acceleration).

This all started after I had the tranny fluid flushed at the dealership, but they swear it has nothing to do with that.

Please let us know if you find out anything from your dealership.

I started a thread on this same topic:

RTSGS57 · October 3, 2019

UPDATE: I've been round and round with the dealership and they have said over and over that this surge, hesitation, shudder, whatever you want to call it, is normal. They drove it, acknowledged that it is performing as I said, and ran all of their tests to make sure that it wasn't an ignition problem. The final explanation is that the torque converter clutch is slipping, it's built into the operating software and it is designed to operate that way so it doesn't overload the torque converter under a heavy load. What?? What a joke and a lame excuse. I'm just going to start being a pain in the butt. I'm not settling for such poor drivability and performance for a $50,000 vehicle.

I've heard a lot recently about poor quality and engineering from GM but they've been making this 6.0 motor and 6L90 transmission forever. I thought for sure it would be a solid, reliable combination.

Edited October 3, 2019 by RTSGS57
Additional info

RTSGS57 · October 3, 2019

On 9/26/2019 at 2:29 PM, GTBensley said:

I think a few have had similar issues and it ended up being to torque converter. I wouldn't settle for normal, mine doesnt do it.

So did they replace your torque converter?

GTBensley · October 3, 2019

No, I am saying that others have had similar issues. A shudder is not normal, my truck does not do it and never has.

I know others here have had them replaced

rickit · October 3, 2019

my 2016 has always done it feels like my old camero did with manual trans

dozerboy · October 12, 2019

I got 2 2015+ trucks and don’t have this issue and they have over 150k on them.

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steelcity · October 18, 2019

My 2016 has done it from day one. No biggie, just noticeable.

AbzDad · October 21, 2019

I tried a "fix" that some of the 1500 guys have used with mixed results. I turned off Grade Braking by holding the trailer button for 5 seconds when i start the truck. The screen will confirm that Grade Braking is off. It reduces how noticeable the shuttering is on my truck. It is not a complete fix, but does seem to reduce the frequency and severity of the shuttering. You have to turn Grade Braking off every time you start the truck

FLORIDAMK · October 25, 2019

I had my torque converter go bad a few months back, 2015 6.0 with only 50k miles. Tranny was acting erratic and tranny oil temp jump up to 250 degrees.

RTSGS57 · December 14, 2019

On 10/3/2019 at 3:43 AM, RTSGS57 said:

UPDATE: I've been round and round with the dealership and they have said over and over that this surge, hesitation, shudder, whatever you want to call it, is normal. They drove it, acknowledged that it is performing as I said, and ran all of their tests to make sure that it wasn't an ignition problem. The final explanation is that the torque converter clutch is slipping, it's built into the operating software and it is designed to operate that way so it doesn't overload the torque converter under a heavy load. What?? What a joke and a lame excuse. I'm just going to start being a pain in the butt. I'm not settling for such poor drivability and performance for a $50,000 vehicle.

I've heard a lot recently about poor quality and engineering from GM but they've been making this 6.0 motor and 6L90 transmission forever. I thought for sure it would be a solid, reliable combination.

I've decided to just not worry about it. Either it's not as pronounced as it was or I'm getting used to it. I work on the road, not home very much, and I'm not spending my home time battling with GM. I'll trade it before it's out of warranty anyway. On what, I have no idea. Thanks for the help and info shared.

gearheadesw · December 14, 2019

I thought I read on here somewhere that it was traction control induced, haven't the faintest idea how, but it could happen.....

RTSGS57 · December 15, 2019

13 hours ago, gearheadesw said:

I thought I read on here somewhere that it was traction control induced, haven't the faintest idea how, but it could happen.....

I was searching around the forum and found an opinion about the traction control and tire pressure causing the problem. Supposedly if you have no load, you can get a little wheel hop or jitter over small bumps with 80 psi at the rear tires and It can cause the traction control to kick in and cause the feeling of hesitation or shudder. It seems if you lower your tire pressure to say 50 to 60 psi it goes along way towards solving this problem. The ride of this truck with no load and the tires at 65 psi front and 80 psi rear is abysmal anyway. So I'm going to give that a try.

Edited December 15, 2019 by RTSGS57