The SD I am acquiring this weekend had a rebuilt unit installed AT THE DEALER for 1900 bucks. That was a couple of years back, so unless they have become scarce I can't imagine the work being that much more. (It was 4 hours labor at even 100 bucks/hour, leavines 1500 for a unit). Maybe find a tranny specialist? A mechanic who is a friend of ours charges OUTRAGEOUS prices on tranny's, as he would rather not do the work. But if you are a payin'....
I could think of a lot of things I could do with the extra 3K.