94 le tranny prob

i got a 94 le sentra, the tranny only works in first gear so far, and hits about 30, and im not sure how many rpm cuz i dont have a tach, it doesnt shift, somtimes it hits 2nd, but just clicks back really fast, im not sure if its the tranny or like a problem with the computer because the tranny only has 60,000 on it.If anyone has any suggestions please leave a message or email me, my sn is whitepolishrappa if ur using aol instant messenger.