Technical Rear end ID?

Can anyone help ID this rear end? 4 3/4 pattern, 14 bolt, 54 inches backing plate to plate. Thanks ET

 

how about a picture of the whole thing? including the brakes, etc.

 

1957-59 Cadillac. There is a small one digit number stamped on it that tells the gear ratio. If there is a letter with the number it is a limited slip differential.

 

Appears that it is geared 3.21

 

I recall Caddy rears being an absolute bitch to work on! Totally off the wall weird design. I would never touch one again!

 

Thanks.
ET

 

I had a customer blow up a '58 caddy rear. I went looking for parts and could not find any info. caddy repair manual and Motors manual listed "no service" info. replace whole unit.
really a stout unit and should last a lifetime.............if there is oil in it.