you'll be looking to spend ~ $1400 for a tranny build, or...
http://sd.craigslist.org/pts/1019807839.html
I paid $600 for mine a year ago. after the smoke settled I had $1100 into it. then I sold the good spare 4.3 and got $500 ahead. but this summer I will need to go through the tranny. imagine that, huh.