Alright, a friend of mine has a 99 7.3 that will run great with an 8,000lb load and back up with the load no problem. but when hes been driving around all day with the load and the transmission temp is warmed up and he tries to back the load up a slight incline and it doesnt have the power to do it. is it normal for it to have that problem or is there somethin goin on somewhere. he says 95% of the time it has no trouble with backing it up a hill at all.

 

The torque converter clutch is trying to apply in reverse.

It's a common problem with aerated fluid, leaking internal seals, scored or worn pump, or even just low fluid levels.

Tranny rebuild time with a new pump.

 

Exactly...

 

alright. thanks fellas