Rebuilt tranny - is it still under warrantee? Is the fluid a healthy red w/o a burnt smell? Does it shift smoothly w/o slip or flare?
When my (9k Aamco under warrantee) tranny first started to go, the shift from 2nd to 3rd felt like I was lightly hitting the brakes despite the RPMs climbing a bit more than they were supposed to. Then the fluid changed from grenadine red to BBQ sauce and the shifts felt like I was being rear-ended with each 2-3 shift and the tranny made a pitiful grinding noise. So don't buy a car that feels like that.