Rear end Clunk

[dgirouard39]

2019 (new model) elevation x31.  

Coming to a stop I get a clunk in the rear end its pretty viscous at times.  

i took it to the place i bought it from and they said that is normal for these trucks. how is this normal????

feels like the when you are towing something and then you stop and the trailer ball slides a tad....

 

Def thinking its drivetrain or tranny issue.  

[RWTJR]

On 11/17/2020 at 7:25 AM, dgirouard39 said:

2019 (new model) elevation x31.  

Coming to a stop I get a clunk in the rear end its pretty viscous at times.  

i took it to the place i bought it from and they said that is normal for these trucks. how is this normal????

feels like the when you are towing something and then you stop and the trailer ball slides a tad....

 

Def thinking its drivetrain or tranny issue.  

Sadly, I think GM often confuses "common" with "normal". What you are experiencing is pretty common and is often excused away by GM as normal. My understanding is it's caused by the transmission holding 3rd gear as you slow down in order to save fuel (anticipating you'll speed back up). When the transmission realizes you are stopping instead of speeding back up it downshifts from 3rd to 1st and gives that bang and the feeling like someone just tapped your bumper (commonly known as a harsh 3-1 downshift).

 

If you have another dealership you can go to, do so. I know some have reported improvement with a TCM reprogramming but finding a dealership willing to do it under warranty (or at all, because it's normal) is another issue. If you don't get a resolution from a different dealership, contact GM customer care.

 

Good Luck

JMHO

No expertise implied or expressed

[SPASierra]

Hopefully someone will crack the ECU and shift points can be fixed with a tune.  Mine does the same thing, and I knew what it was the first time I drove it.  It's annoying, but really there isn't much that can be done unless GM has an alternate shift map that dealers are authorized to program.