i've got a 92 4x4 with a e4od and it shifts hard. mainly from 1st to 2nd, i was told that a wire for the torque converter lock up was probably unhooked, but i checked all the wires i could see coming off the tranny, (the only ones i seen were on the drivers side) is there a non visable wire some where? i've crawled all over this thing,
the mechanic i talked to said it wouldnt do anything to the tranny, and alot of people unhook them anyways. but i dont want to take any chances and burn up my tranny, the engine and tranny were just rebuilt in late 07 before i bought the truck.

 

Check the VSS wires on the differential.

 

Mine was shifting fairly hard too - after checking to make sure wires are all good (and replacing bad wiring if it's there), you might need to look further. I replaced the VSS on the tranny, the RABS on the rear diff, and the TPS on the throttle body. I also had it flushed and filled with synthetic fluid. Between those things, it's shifting silky smooth now.