95 aw4 problem???

I pick up a 95 xj a few months back with some problems for dirt cheap. The kid I bought it from said he was driving, slowing down to a stop sign, when he started to go again he had nothing and the trans let out a squeal. What do y'all think it is, trans actually went out or did the torque converter go? I have no forward or reverse. Starts fine, when I put it into "gear" the engine revs up and returns to normal.