Cool site ... I love my 325e, having some tranny problems, though

. My question for the experts or experienced is , I have found a 1984 318i 5 speed manual, in good shape and for only $400. Engine problems!
I own a 1985 325e manual 5 speed. Looking at several sites I see the same part numbers used for both. Other references leads me to believe they are different trannies...
Would anyone please be able to shed some light for this newbie, or at least point me in the right direction.. THanks Guys.