I have a 96 f150 with 4.9l and 2wd e4od. I recently developed a transmission leak from the bell housing. Transmission operated correctly until I towed vehicle to a shop and then pulled tranny and replaced front and rear seals and the rear main engine seal (since I was there). After replacing seals and checking/ adding fluid then running through the gears. everything seemed fine until I took her on the highway. It never shifted into 3rd or 4th and the leak was fixed.I then removed tranny again. drained torque converter. checked internals of torque converter and all electrical plugs. reinstalled tranny after finding no apparent issues or damages. I then connected obdII scanner for codes and got none. no flashing OD lights. no noises. no trouble shifting into reverse or 1st and 2nd. no clue where to go from here. any advice would be greatly appreciated.

 

My guess is a stuck 2-3 shift valve in the valve body.