Help. I can't figure out the rear end in my car. Originally it came with a 3.08 standard axle. This one is a posi 10 bolt. Only numbers I found on bottom of housing are: N 1235542 And GM 18 I scrapped off drivers side rear tube and found no ID letters. Any ideas where they might be. I'm guessing gears are 3.23 from the turns. Thanks Carl
