Hey gang,
I know this was adressed (sorta) in a recent thread, but I'n not seeing any real answers. My wife's '08 has distinct freeplay or slack in the driveline. It does NOT clunk going from reverse to drive, or during hard braking or cornering. But coming off the gas for a slower driver, it clunks when you accelerate. The harder you hit the gas the heavier the clunk.

The shop where I get the oil changed talked me into changing out the u-joints. I did it because they have 120k on them but I knew that wasn't the issue. Guy actually showed me the slack, I could see that the entire driveline was moving, and there was no detectable movement between the u-joints and the yokes. But they're done now.

My '04 with 150k on it doesn't do this. Is it just a 6.2/6L80 thing? Is there a backlash adjustment for this? I had the tranny flushed hoping it would improve it some, but no luck there. Mulepic said this in another thread: "I have this issue in my 2008. I'm starting to accept the fact that it's 'normal'. But I think it's either the tranny or the chain in the transfer case. I've replaced my u-joints on the front and rear driveshafts."
So there's that, too. I've tried to research the transfer cases to see if they are the same on all year models but haven't found anything conclusive yet.

I don't want to just live with this, especially since I'm looking at trading the '04 for another '08. So looking for ideas from the community. Any help would be appreciated.

 

This may help.


Some customers may comment that the vehicle has a “Tip In” low speed clunk in first gear when the throttle is applied and released in normal “D” drive. Other customers may comment on an engine braking sensation at low speeds in normal “D” drive.


<a id="d98898e24">CorrectionA revised transmission calibration has been developed to address these issues. Reprogram the transmission control module (TCM) with updated calibration files using the TIS2WEB Service Programming System (SPS) application. As always, make sure your Tech 2® is updated with the latest software version.

 

Models: 2008 HUMMER H2, H2 SUTwith 6L80 6-Speed Automatic Transmission (RPO MYC)

 

Thanks. Found the rest of it over on elcova. Be nice if I could join that one...

Hi sounds like most dealers, remember it was only a $60,000 truck hehehe, their is a program update for some 2008 i had it done. I had to tell the dealer their was a TSB for the trans because they did not know about it. After i told them they checked for the TSB then they would reprogram it for me. This TSB will not be your problem but here is the TSB below. The dealer will not tell you about it you must bitch about the trans clunking in first gear when the throttle is pushed then released. Then they will reprogram it.


TECHNICAL

Bulletin No.: 08-07-30-012

Date: March 13, 2008

Subject:
6L80 Automatic Transmission - Tip In Low Speed Clunk in First Gear When Throttle is Applied and Released, Engine Braking Sensation at Low Speeds (Reprogram TCM)

Models:
2008 HUMMER H2, H2 SUT

with 6L80 6-Speed Automatic Transmission (RPO MYC)

Condition

Some customers may comment that the vehicle has a "Tip In" low speed clunk in first gear when the throttle is applied and released in normal "D" drive. Other customers may comment on an engine braking sensation at low speeds in normal "D" drive.

Correction

A revised transmission calibration has been developed to address these issues. Reprogram the transmission control module (TCM) with updated calibration files using the TIS2WEB Service Programming System (SPS) application. As always make sure your Tech 2(R) is updated with the latest software version.

Warranty Information

So I guess I'll call the local GM boys and see if they can do this. Thanks.

 

Wow, good job finding that. I hope it works b/c I gave up and resigned to living with it. But it scares me b/c we tow w/ ours. Let us know how it works out.

 

My 09 w/ the 6L80e is doing the same thing. It's really bad. I can't even accelerate normally anymore. I go into overdriver or 2nd overdrive a LOT, along w/ this awful cluck going from breaking to giving it a little gas.

Maybe this is the fix.
I'm curious how much this is & if it's worth even doing if I'm going to be swapping out the power train anyways.


Please update the thread once you have it done. Oh & do it soon.

 

I would think a TSB like this wouldn't cost anything, but I have yet to bring this thing into a stealership.

 

bulletins are not recalls simply published to aid in diagnosing concerns, unless vehicle is under warranty it will not be a free repair. Typically a reprogram of a module runs 1 hour labor time.

 

Well if flyday58 finds out that it works then I think it's worth it.

 

Waiting for a dealer service rep to call back...