Sc00by

So I have a new to me 2017 GMC Sierra CCSB 4x4 Z71 w36k on the clock. Before purchasing this I was aware of potential issues with the trans and random vibration issues that lots of people have been having. Turns out a have a whole lot of both. I love the truck but it’s already spent a week at the dealership for some issues. One issue was with the transmission which seemed to be slipping while accelerating with moderate throttle. The dealership claimed it was an issue with the fluid and how the type of fluid messes with the torque converter. The dealer said it needed to be flushed with a new type of fluid and it will fix 90% of the vehicles that receive this service. I had the recommended service done and it seemed to work for about 1,200 miles but is starting to show signs of the slipping happening again. The dealer claimed if it came back that it was likely going to need a new torque converter. This seems odd to me and where my question starts….. First off is this dealership B.S. with a fluid affecting a transmission like this? Especially a torque converter? And is it worth my time to have them put another factory TQ converter in for it to potentially have the same issue vs me just putting an aftermarket one in and not having an issue again? I do plan on modding this truck once I get comfortable with it and my 60k mile power train warranty is a little closer ending. Any kind of info on this transmission would be helpful. I’m used to my 4L60e issues on my old truck but this one is new to me. Thanks guys for your help!!

BudRacing

iTrader: (3)

I wouldn't go aftermarket just yet--especially with all of those warranty miles left. If they're replacing the converter with a revised part number, I'd give them their shot.

FFDP

iTrader: (2)

Torque converter issues are pretty common on the 8L90e, let them replace it if it's under warranty.

Sc00by

I'm going to make an appointment to have them take a look at it again. I guess im so used to my old truck without a warranty. If something wasn't working properly I would replace it with an upgraded part. Thanks guys for your advice!