Stealth auto trans

I don't recall which trans is in the '91 Stealth, but generally a rebuild by a reputable transmission shop could run close to $1000. I think your best bet would be to call around to some wrecking yards and get a used trans from another vehicle, the wrecking yards also have "interchange" manuals which tell you what other vehicles use the same tranny. You can probably get a used unit from a wrecker for maybe $400 and either put it in yourself if you have the knowledge and equipment, or get a garage to do it (it's not a big job for them) total probably around $500, 1/2 a rebuild. Most wreckers also give a short (30 to 90 day) warranty on used items they sell.