I have a 1996 GMC Jimmy 4x4 V6, my trans is gone and I would like to know if I must used a 96-97 trans as a replacement? If possible what other years will what?

It is probally 1996 only and check this with a junkyard that has an interchange book called the Hollander.I know is 1996 on the fullsize pickups,tahoes,suburbans and is the same with the Jimmy and blazer.You might want to check the cooler also,blow through with a rubber tipped air nozzle.It could be plugged and will cause a transmission problem down the road.If it is plugged,a new radatior or bypass that one with a transmission cooler.