I have a 2007 AWD Sierra Denali, sometimes when you give it gas and its in first gear, then let off and it shifts to 2nd, it has a loud clunk. Big enough that you can feel the drivetrain bounce or shake or something. Anyone else have anything like this happen? I just bought the truck so trying to figure out some little issues. If it's going to break, I'd like it to break while under warranty still lol

 

Is your truck tuned? If so, how much tq managment is removed?

 

Nope. completely stock

 

Does it do it when you first start driving (when its cold) or will it do it after the tranny is warmed up?

 

Its done it both.

 

Sounds like your playing with the pedal while it shifts. Just drive it normal.

 

Definitely not the case.

On further testing, its only the 1st to 2nd shift. It feels like sometimes 1st gear doesn't want to let go then it does and it SLAMS into 2nd. It would do it repeatedly last night while I was driving slowly through a neighborhood looking at houses.

It's loud and shakes the whole truck.

 

I wonder if it has some sort of tune in it and the dealership isn't aware of? My truck on the stock tune can't wait to get out of first gear. By that I mean when you would take off it seems like it would almost immediately shift into second gear and was soft and quiet.

 

I wonder that myself. I have to take it back and have them clean something they said they'd take care of. I wonder if they would flash the computers in it for me. It is a GM dealer.

 

i rode with him the other night to see what it's doing and this truck DEFINITELY has a stock tune. the once or twice i kind of heard it sounds like a little extra backlash in the rearend or transfer case. has that loose mechanical sound

i gotta say jeff, it's pretty dang minor and i would just drive the truck until it becomes more noticeable or just take it to a dealer but i doubt they'll find any problem as it sits now