Rear axle on my P15 question

[BobT-47P15]

Many years ago my P15 was in some type of accident.....my guess is running off the road and perhaps hitting a culvert.  They replaced the original rear axle with one we 

think came from a 1939 Dodge pickup.  Are there any numbers on that housing which might serve to identify from what the axle and differential came?

Any info appreciated.       Bob

 

edit::  in P15 parts manual,,,,,CASE, differential, (all except station wagon)   :    670 583

 

Numbers found on diff now in car (which we think is a 39 pickup item)   :     663 473 - 12.

 

Any thoughts?

Edited September 1, 2019 by BobT-47P15