so aw4 tranny problem...(many others too)

first a short story..ok so a friend owed me like 200 bucks .. sooo he gave me his 88 cherokee 4wd... i drove it home running like crap and the rearend sounding like a lion..(it was roaring pretty loud).. so a another friend gave me a 96 grand cherokee with a bad tranny ... so i pulled the rearend out.. n figured i do i rear end swap...which i got all that done... then i tried to back it out of my drive way.......it will not go in reverse.. i then change the filter and put new fuild in .. it was really black... still no reverse.. i took the dash apart and found that the tcm has a yellow wire running to it with a fuse someone put on it running to some blue wires??? is it this or do i just need to drive it and not go in reverse...until i can get some cash for a tranny?? i havent heard of anyone having this problem with an aw4..

and on the grand cherokee if it was built in 1/96 is it still a 96??