Well, all I can tell you is that I had a near new Starter on the 94 Geo Metro/Auto trans car I HAD been driving, When the Auto trans died and I Picked up a 94 Metro with 5 Speed manual trans, then did an engine swap into the 5 speed manual car, The starter from the Auto Trans car
Would Not Fit....
. I had 2 other starters from manual trans Geo's and had to use one of them! The Auto trans starter I sold to the highest bidder off on E-Bay for $30.00 , less than 1 year old and I paid $98.00 for it...
. However, it was of no use to me anymore! Cant say for same for sure on a 1990....But the 94 Auto and Manual trans Geo starters didn't interchange on the cars. They were different part numbers on the AC-Delco website as well. BTW, I dont know why the Auto parts store is telling you there is an $80.00 price difference between the 2 starters....Advanced auto parts website shows the Auto trans starter at
$118.88 and the Manual trans starter at
$108.88.