tranny problem

[tj92explorer]

i bought this truck from a friend the front drive shaft was layin in the back when he bought it it was blowin tranny fluid so he had the tranny rebuilt i have since taken it back to the shop 6 times they dont have a clue whats wrong at one point they charged me 700 for a new computer anyway my problem is that while driving. it will kick itself out of gear mostly highway but sometimes city drivin may do it everyday or once a month i was told today it was one of 2 things the filter because i have to pull over and put it park to get it to engage but sometimes i can coast in gear for a short and feather the throttle and it kicks back in but it seems if i let it sit it will run better for a while the other opinion i got was since the in cab transfer case light wont come on and you cant get the transfer case to do much which like i said it has no front drive shaft but that opinion was its the gear in front of the transfer case that has worn down and is disengaging and kicking the tranny out of gear but i replaced the filter and test drove and it ran fine but that doesnt say anything. it doesnt do it all the time sorry for rambling this is expensive and killin me anybody please help by the way:fire: im new on here hello to everyone