Seriously bummed here. I had a bum 2nd gear.... so over the weekend I swapped for a trans from a parts-car.... only to find it has a bad 1st gear....

Maybe there's an adjustment of some sort y'all can tell me about? I know I need to adjust the clutch (frisction point is waaaay at the bottom of the stroke), but it seems like it isn't fully engaging 1st gear. it kicks-out the moment power is applied. well... more accurately: it seems to jump out/in repeatedly. makes a nasty noise and banging.
and otherwise: can anyone recommend a trans rebuilder that I can send the one I just took out to for a rebuild? Or should I attempt myself?