Pretty stout trans - I have one in my 95 s10 with 231K miles on it. Synchros work although I think I have a failing input bearing.... least of my concerns with that truck at the moment...way better than that New Venture 1500 or 3500 they put in the s10's after 1995.
Be aware depending on year it is and what its out of it may use straight ATF or 80-90w...