2015 Yukon Denali - first shift of the day between 30-40 mph is super rough

[sandyjk]

First post here...newly converted from Ford and my husband is laughing because I'm having problems within two weeks of buying this car. First drive of the day, when I'm accelerating and I get to about 35 mph, the shift actually lurches the entire car. The dealer is going to replace the transmission fluid with a new updated fluid. Has anyone else had this issue and how was it resolved?

 

[mb1500]

The 8 speed is sensitive to the proper fluid (needs the updated one) and it needs to be in good condition. Hopefully the dealer will resolve your problem with the new fluid.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

@NickTransmissions

 

[NickTransmissions]

Thanks @Joseph Garcia

First post here...newly converted from Ford and my husband is laughing because I'm having problems within two weeks of buying this car. First drive of the day, when I'm accelerating and I get to about 35 mph, the shift actually lurches the entire car. The dealer is going to replace the transmission fluid with a new updated fluid. Has anyone else had this issue and how was it resolved?

Im not yet familiar with the 8 and 10 speed transmissions however i know they use a different fluid than Dex6 used in thr 6 speeds and that shifting/drivability issues arise if the wrong fluid is used (fluid formulation is driven by clutch material composition, in laymen's terms).

Additionally, the 8 speeds are the subject of a pending class action lawsuit that applies to several models/sub models manufactured between 2015-2019. The drivablility symptoms are essentially identical to what you're experiencing. Source of the problems are said to be valve body and incorrect fluid formulation.

To me it also sounds like potential faults in either the vehicle ECM's command and control logic or downstream sensors/switches in the transmission control module (We see harsh/lurching shifts when the 6L transmission control module aka TEHCM malfunctions).

Let us know how it drives once the fluid is flushed/exchanged. Hopefully this is being cared for under warranty.

 

[waterman]

Hello,

I am having a similar problem. If you don’t mind, can you tell me what the cost was?

First post here...newly converted from Ford and my husband is laughing because I'm having problems within two weeks of buying this car. First drive of the day, when I'm accelerating and I get to about 35 mph, the shift actually lurches the entire car. The dealer is going to replace the transmission fluid with a new updated fluid. Has anyone else had this issue and how was it resolved?

 

[duke90]

Hello,

I am having a similar problem. If you don’t mind, can you tell me what the cost was?

Had the same issue and the Yukon would jerk forward when slowing down from 2nd to 1st gear and almost coming to a complete stop. Trans flush was $375 at the dealer. They also said I needed a software update. Drove a little better after getting both of those done but the issue was still there. Changed the driver’s side motor mount and behold, issue is gone.