Post this over in the windsor power forum and you will get more responses. I am sure if mod sees it here, they will move it for you.
Is the car actually backfiring, or just making a popping sound? Mine used to "pop" throught he exhaust, but it wasn't as loud as a backfire. Turned out I had a bad fuel injector that was causing the problem. I don't know if that helps you or not, but that was the case with mine. I am not sure if the tranny is related or not. I guess it could be if it is a vacuum problem
. I dunno.