2015 Sierra 8 Speed Trans Issues

[Smoke244]

I purchased my 2015 GMC Sierra Denali used almost a year ago and I am experiencing delay shifting when cold going into reverse or drive and also have hard shifting from 1st to 2nd while the transmission is cold. On occasion I also am experiencing a hard downshift.

I have dicussed this with my dealer and I’m told this is normal for these 8 speed transmissions. The fluid has been recently changed.

is everyone just dealing with this or is there a fix for this?

 

[G-597660]

I purchased my 2015 GMC Sierra Denali used almost a year ago and I am experiencing delay shifting when cold going into reverse or drive and also have hard shifting from 1st to 2nd while the transmission is cold. On occasion I also am experiencing a hard downshift.

I have dicussed this with my dealer and I’m told this is normal for these 8 speed transmissions. The fluid has been recently changed.

is everyone just dealing with this or is there a fix for this?

Same problem with my 2016.

 

[Smoke244]

Same problem with my 2016.

Ouch, was hoping for better news than that. A real shame GM doesn’t have a better answer for this.

 

[Dan_in_WA]

Had the same problem in my wife’s ‘01 Montana.

The fix was to order a kit from TransGo for that particular transaxle, it had an oversized rubber seal that fit around a (IIRC) piston inside the trans.

Cold weather caused the original seal to contract enough that the fluid would leak past it. Until the transmission warmed up a bit, no reverse!

The TransGo seal fixed it completely.

General Motors Products

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