Hello I have a 4l80e in a 1998 Chevy 6.5 4x4. I blew a transmission line and lost 3 quarts of fluid. Fixed the line and filled transmission. A week later transmission started slightly slipping. So I pulled pan, changed fluid and filter, there was No metal in pan, slight burn smell to the fluid!. Truck ran great for about a month. Then after about 15 minutes of normal driving one morning the transmission mad major slippage in all gears. I Pulled over, parked overnight. Next morning drove it about 15 minutes with all gears, running great then is started slipping, barely got it home with major slippage again? Pulled pan again, no metal but fluid has a slight burn smell again! Truck is also not blowing any codes!

 

sounds like a accident smoked a already weak trans.

 

If its slipping after you get heat in it, gonna have to come out and gone through !!! Sealing rings possibly ,clutches ?? Hard to determine until you look inside

 

Actually after countless hours of research, like every other issue with my rig!

It was a bad torque converter! Changed it out and my truck is on the road again!