Identify Posi Unit

[blk68gto]

Can anyone tell me what this unit is? Friend of mine got it with a bunch of late 50s and sixties chevy stuff he thinks. Two pictures, if I can get them in attachments right. Numbers are, 2RX GM3756448 12 37 6 63 Inside has 18 teeth

['ol Pinion head]

Ring gear & carrier are out of '64 Corvette. This early style posi is not as desirable as the Eaton (ED 32297) which replaced it.

Often, inside the carrier, one or more corners of the two alloy divider plates (spring locators) will have broken off, not allowing one of the long posi preload springs to seat. If such is the case, the carrier is basically good for parts. Been through this before http://forums.performanceyears.com/groupee_common/emoticons/icon_frown.gif

[blk68gto]

Thanks Pinion Head, sounds correct to Larry. Mike Lemley