GM 6 speed auto- Clunky?

[deerefan]

I have a 2011 Silverado 4wd with the 5.3 and 6 spd auto trans. I like the truck, not real sure of the trans. It makes a clunking sound downshifting, done it since new. Dealer checked, all normal. Also, if I hit the brakes, sometimes it will "push" me slightly when downshifting into 1st. Anyone else experience these issues with this tranny?

 

[crashz]

I'm not sure of they share the same transmissions but my 2500HD has the same issues (6 speed auto). Clunks going from 3rd to 2nd when you slow down enough downshift but have to lightly accelerate a moment later.

Dealer told me the same thing. When I was trying these trucks out, two of them did it. My old 4 speed did it too. It's irritating, but normal. Or at least common.

 

[dkhntr04]

The 6-speed in my '07 2500HD will clunk at low speed/throttle up-shifts from 1-2, or 2-3 now and again. Dealer said nothing is out of the ordinary when I took it in under warranty.

 

[deerefan]

Good to hear its not isolated to me. It is rather annoying.

 

[Dmace]

Does it do this in Tow/Haul too?

 

[timswi]

I have a 6sp in a 2011 GMC 6.2...I don't fund it clunky at all...Sometimes if you catch it between gears on a downhift it can be a little harsh, but that's normal.

 

[kevinj]

The engine braking part can seem clunky I guess but mine is an 08 and has been the same since new. Always works fine. GM did have an issue with the trans tailpiece/drive yolk that needs a special grease on the splines or it will clunk if it cannot slide easily.

 

[deerefan]

Does it do this in Tow/Haul too?

Not that I recall.

 

[deerefan]

I have a 6sp in a 2011 GMC 6.2...I don't fund it clunky at all...Sometimes if you catch it between gears on a downhift it can be a little harsh, but that's normal.

Yea, that downshift gets me sometimes. Feels like a slight lunge forward, even when brakes are applied. This is my first 6 spd. All other trucks were torque shift fords, 4 spd gm/ford or manual.

 

[crashz]

Mine has not done it in tow haul either. Won't do it during manual up shifts either.

 

[tcreeley]

My 2003 2500HD auto 6 liter has never clunked 2wd, towing or not. I'll get that when I go into 4wd and out sometimes at a stop.. Must be something new.

 

[case245]

i have a 2011 3500hd mine doesnt clunk at all a bad u joint on the rear driveshaft maybe it doesnt happen when going in to 4wd i hear a clicking that it i have a floor mounted shifter

 

[deerefan]

i have a 2011 3500hd mine doesnt clunk at all a bad u joint on the rear driveshaft maybe it doesnt happen when going in to 4wd i hear a clicking that it i have a floor mounted shifter

You have the allison correct? Mine is a 1/2 ton.

 

[Diamondpilot]

I would check your U Joints and Carrier Bearings if equipped. I have done quite a few in GM trucks as of late. Don't bother letting the dealership fix it under warranty. They just put in the same crap part and you will be doing it again in 25,000 miles. I know of a truck that is on its 4th in 80,000 miles. This last one I did with a aftermarket Moog.

One other though is the transfer case. They have a pump rub issue. Could the noise be coming from it?

Chris

 

[deerefan]

I would check your U Joints and Carrier Bearings if equipped. I have done quite a few in GM trucks as of late. Don't bother letting the dealership fix it under warranty. They just put in the same crap part and you will be doing it again in 25,000 miles. I know of a truck that is on its 4th in 80,000 miles. This last one I did with a aftermarket Moog.

One other though is the transfer case. They have a pump rub issue. Could the noise be coming from it?

Chris

Not real sure. It is not a ujoint, had those checked by local mechanic. It is coming from the trans, not all the time, almost like I catch it between gears. Done it since new with 7 miles on it.

 

[Bigkrank]

Pump rub issue only on older than 2007.5.

 

[Ryan03]

I would check your U Joints and Carrier Bearings if equipped. I have done quite a few in GM trucks as of late. Don't bother letting the dealership fix it under warranty. They just put in the same crap part and you will be doing it again in 25,000 miles. I know of a truck that is on its 4th in 80,000 miles. This last one I did with a aftermarket Moog.

One other though is the transfer case. They have a pump rub issue. Could the noise be coming from it?

Chris

I beleive the pump rub is a 2007 and earlier issue.