Hey guys I have a 2012 z71 5.3 with 6 speed with 1500 miles and the past couple days Ive noticed when first started and cold when the truck shifts ...

Hey guys I have a 2012 z71 5.3 with 6 speed with 1500 miles and the past couple days Ive noticed when first started and cold when the truck shifts between 2-3 it slips the tach will go from ~2000 rpm up to about2500 then back down where it should be i took it to the dealership already and it did it all the way there and of course as soon as the tech got in it wouldn't do it. So I'm going to have to give them my brand new truck overnight. What's up with these trannys my dad bought a 2011 and gm is having to put a new one in it as we speak, but for different reasons.

I haven't had any experience with the new GM transmissions, but I'm interested to see what the dealership says. Let us know!

Pretty shity coincidence I think. I've had 3 new trucks over the last 3 years and haven't had a stitch of problems with them. (knock on wood) I know the new tranny guy at my old dealership has had it pretty slow.

Man it's crazy at least I have another 98000 miles of warranty. one of the trans guys at the dealer my dad took his to said he's been having a decent amount of issues and gm is finally telling them there are problems rather than its learning how you drive and all that jazz. At first gm had them replace the torque converter, then the Tcm, now the trans.

Wow, I agree that it's coincidence. Mine is rock solid, and we have not hear a lot of issues with the 6 speed here on the site. Agreed that it's good you have a 100k warranty!

In all the reading/research I did before buying my 2012 I don't recall coming across any transmission issues. Other than a few where people were trying to get used the the different feel. Hope they get you fixed up.

Mine does this too when it's first driven on cold mornings. I noted it as more of a delay in shifting, and agree the RPM's do rise a little prior to hitting the next gear. I recall reading something in the owner's manual about this and so far written it off as 'normal' when it's cold. Once vehicle warms up it's fine. Also noticed that this occurs more frequently if I get on the gas a little more - again issue disappears once vehicle is up to operating temp. Let us know how it goes though.

Will do guys the trans guy at the dealership said if its doing that between shifts it's not normal so I guess well see.

The longer hang in gear when cold only applies to the 1-2 shift....I think.

Have you try it in manual? The following is from a 2011 Owner's manual;

The vehicle has a shift stabilization
feature that adjusts the transmission shifting to the current driving conditions in order to reduce rapid upshifts and downshifts. This shift
stabilization feature is designed
to determine, before making an upshift, if the engine is able to maintain vehicle speed by analyzing
things such as vehicle speed, throttle position, and vehicle load. If the shift stabilization feature
determines that a current vehicle speed cannot be maintained, the transmission does not upshift and instead holds the current gear.
In some cases, this could appear to be a delayed shift, however the transmission is operating normally.
The transmission uses adaptive shift controls. Adaptive shift
controls continually compares key shift parameters to pre-programmed ideal shifts
stored in the transmissions computer. The transmission constantly makes adjustments to improve vehicle performance
according to how the vehicle is being used, such as with a heavy load or when temperature changes. During this adaptive shift control
process, shifting might feel different as the transmission determines the best settings.
When temperatures are very cold, the Allison Transmission and Hydra-Matic 6-Speed transmission's gear shifting could be delayed
providing more stable shifts until the engine warms up. Shifts could be more noticeable with a cold transmission. This difference in
shifting is normal.