ug87

They ended up having my truck over 5 weeks. They took the transmission out a second time and replaced more 4-5-6-R clutch parts. Not sure exactly what they replaced yet, waiting for all of the paperwork to be sent over. That's fixed it so far.

So after changing the upper and lower valve bodies, they removed the transmission and disassembled it. They found some bad internal parts and are changing them, clutch housing, seals, and piston.

My 21 Sierra SRW is in the shop for something similar. Put it into reverse to back into my driveway(slight hill) and it revved to over 4000 rpms and barely moved in reverse. Moved it through all the gears and let it sit and it did it again. We'll see what the shop says. There was no noise, clunking, or smells.

2021 GMC Sierra HD 3500 Denali Crew Cab, Standard bed 6.6l Gas $64k after Employee pricing, Costco, and adding the GM extended warranty

Just got my truck today. Opted for the GM extended warranty, it was only $1712.