I own a 88 gmc s-15 2dr 4wd jimmy.I was driving one day, going about 50 and i noticed that the rpm needle was almost red-lining. then after i stopped the truck and started again i noticed that it wasn't going into gear right. it's also leaking something on to the exhaust pipe causing it to smoke from underneath. Does anyone know what this is.I think it's the transmission. How much does it cost to get a rebulit one for my truck. or is there a way to fix it with out having to get a new transmission?