2008 GMC Sierra SLT 272351km

Ok so here's the deal.

As soon as I shift into drive or reverse with my foot on the brake the truck wants to go, I can barely hold it back sometimes, if I am on gravel or wet pavement the tires slip and spin. This is the same when coming to a stop. Always rough shifting to N, P, R because its constantly engaged.

2nd symptom

If I stand still leaning on a curb my truck will not climb the curb and boggs right down when I give acceleration and blows black smoke. On pavement will not do a burn out unless I go into rolling burnout and then **** lets hell loose.

Transmission heats up pretty good as well and whines as soon as put into drive or reverse

Its performance tuned from the dealership, dyno at 495 hp, only after market piece is the exhaust MBRP. this problem has only started 5 days ago.

Air filter is good, oil changed, fuel filter changed, transmission filters and fluid changed belt is good. No codes, brakes are good

Transmission is smooth, shifts smooth, all the gears work, trailer mode manual shifting


I know can't be the only person to run into this problem before. I suggest the torque converter. but trying to figure this out before paying money.

Thanks

 

How hot are we seeing the transmission getting? and how does the trans shift when you are driving it normal?

 

Shifts smooth, highest toe rather stuck in traffic. Was 113c

 

okay that would translate into 235F. Does it drop back down or king of hover there?

 

If I get driving again yes it drops down , that was stuck in gridlock for 20 min

 

does it feel that the Torque converter slips at all? Are we getting any codes?

 

It does now, I'm pretty positive it's the torque converter, been getting a little worse the last couple days. Talked to transmission shops here and they think the transmission isn't unlocking when I come to a stop which in turn would make the problem the converter. No codes

 

Sounds like all your symptoms are leaning toward the Torque converter. How many miles are on the truck?