Occasional sloppy/harsh shifts on '08 Denali (six-speed auto)

[quikag]

It has the "fancy" new six-speed automatic, so imagine my surprise that certain shifts (hard downshifts when going full throttle on the highway, or mid-throttle upshifts through 2-3 gear, etc.) are relatively rough/clunky/sloppy.

Has anyone else noticed the six-speed automatic transmission isn't quite as smooth as it should be at times?

 

[Stargazer]

I notice a hard shift is when I'm in the Tow/Haul mode and downshifting from high speed. But I don't really notice it at other times--maybe when I punch the throttle.

 

[quikag]

It really doesn't happen that often, but I'm surprised it happens at all. The 4-speed is old school, but it's a very smooth transmission. I expected the 6A to be all that and a bag of chips.

 

[Stargazer]

The harshness from the downshifting in Tow/Haul mode is mostly from engine braking. The harshness I get from flooring the gas pedal is mostly a result of the shock on the drivetrain with the AWD going to full throttle all of a sudden. I would get something similar when I took my STI to the drag strip. It's not really from the actual shifting of the gears.

Have you checked your fluids?

 

[quikag]

No, I haven't checked tranny fluids. I would think I shouldn't have to with less than 5k miles on the rig. I really think it's a programming issue with the transmission software.

 

[metro273]

Don't forget that the 6spd is new, so it's in it's test phase right now.
When more complaints come in from you 6spd owners, the GM engineers will come to a possible fix for it.

Can you say...TSB?

Stay tuned...:au:

 

[Rollin Thunder]

Don't forget that the 6spd is new, so it's in it's test phase right now.
When more complaints come in from you 6spd owners, the GM engineers will come to a possible fix for it.

Can you say...TSB?

Stay tuned...:au:

the denali 6 speed has been out for 3 years now. :thumbsup:

 

[Getwired]

the denali 6 speed has been out for 3 years now. :thumbsup:

Well, technically for a little more than two calendar years, and three model years, right?

I occasionally notice a clunk / rough shift, but it's usually accompanied or preceded by a WOT or some other bit of momentary pre-pubescent / adolescent "fun"... :ktoe:

 

[quikag]

I occasionally notice a clunk / rough shift, but it's usually accompanied or preceded by a WOT or some other bit of momentary pre-pubescent / adolescent "fun"... :ktoe:

That is typically when I notice it too. Generally speaking it's a smooth and quiet transmission.

 

[Stargazer]

No, I haven't checked tranny fluids. I would think I shouldn't have to with less than 5k miles on the rig. I really think it's a programming issue with the transmission software.

Maybe it just needs some more miles on it to smooth it out some more?

 

[quikag]

Maybe so? Transmissions are pretty smart nowadays and maybe it's still "learning."

 

[metro273]

the denali 6 speed has been out for 3 years now. :thumbsup:

Doh! Thanks...

 

[quikag]

IIRC, the six-speed auto came out first in the '06 Vette, so it's been out at least 3 years now.

 

[Rollin Thunder]

The most complaints about the 6 speed are on the acadia and enclave forums. My parents are playing hell with their dealer on getting their Lambdas trannys to respond right. Now its nice and smooth and NEVER clunks. But from putting your foot to the floor and the engine takeing off is about a 8-10 second lag (yes that long) and by the time it works up you missed your chance to either merge or pass on the interstate. and power is already lacking on those things. They really need a v-8.

 

[quikag]

Supposedly the Lambdas is supposed to get a V8.