When I was rebuilding my T176 I saw quite a few new & used trans parts on ebay. I ended up buying my rebuild kit from a place in Knoxville called :What Ever It Takes, I had a card but can't find it at the moment. They were very helpful to me and also the cheapest.
Is this T5 close cousin to the 2wd Borg Warner T5 that came out in the S10's, camaro's, firebirds, ford rangers, and many others? If so maybe a gear could be found from a salvaged 2wd trans if they are the same. Maybe you could search by part number if you havent already.