If you told me that 2 weeks ago I would have been able to give you the 5 spd tranny I had from an old 200sx with a GA in it. The car is scrapped now, but goodluck finding one, it shouldnt be too hard all the old GA's are getting scrapped or sold nowadays. Check your local junkyard
Yeah the G20s (I think) had them. Go to your local junkyard and ask them if they have a 5 speed tranny for a Sentra or G20 for whatever year your looking for.