trans problem

hello all
I have my sons 1994 ford ranger in my shop and it keeps popping out of third gear.can someone tell me why?also when you let the clutch out and start moving and push clutch in to coast it feels like a rubber band and it will come to a stop all on its own.I have up on jack stands and it sounds like its coming from the rear of trans or trasfercase.can i split them apart and run the truck to see if the noise is still there?I am a diesel mechanic and have no clue when it comes to these little truck transmitions.thanks in advance wayne

I think your clutch plate is shot. Also your whole transmission needs to be looked over. Unless you have lots of time to spare, I'd just get a new unit, new plate, throw-out bearings, etc. Also make sure the fly wheel surface is in good shape.