Trucks an 04 1500 sierra z71 w/~170000 miles on it. I took it to a local trans shop and after looking at the fluid they said its about time for a $1400 rebuild because the fluid istelf is burnt. I don't doubt that their right because this shift flare has been going on for over a year now. What I'm wonderin is if there are any possible computer/electrical causes mainly because the truck just doesn't run like it should, say driving up a slight incline giving it gas to stay at the same speed instead of staying at the same "power" it seems to bog down then halfway up it will suddenly gain all its power back once I lift off a bit and SLOWLY gain the speed it lost.. Shouldn't it be the other way around? Press on gas pedal go faster? Changed the MAF, didn't help. Then plugs, oil, sea foam, nothing still.

 

At 170,000 its time for a rebuild. Regardless if it's slipping or not, it's probably going to leave you stranded somewhere if it's not addressed. But it sounds like the 3-4's are on there way out.

 

Ouch $1400. I would definitely consider other options/shops if I were you.