I'm looking to get a spare tranny and have it rebuilt since the one I last had rebuilt seems to be going out again after 2 weekends. Probably should have a fresh one on hand at all times.

I hear the .756 5th gear tranny is the one to have, which according to Mazdatrix came in the 89-92 Non Turbo w/LSD RX7's. I do have the 5.12 rear.

There's a local guy who's got a few trannys but he's not sure which exact trim package and year they came from since they are on a shelf. He parts out RX7's and will hook me up for $75 so I'm not too concerned if it's a turd after it's opened up and have to scrap it.

Question: Is there anyway to tell if a tranny (w/o tearing it apart) has the .756 5th gear when you don't know the donor car?

Thanks!