TimberDawg,
That is an "Eaton" axle. GM outsourced axle manufacture to Eaton for their 3/4 and 1 tons from early on (46 maybe) up untill 1972. It is a super strong, "full floater", "removable 3'rd member", axle. Only problem is you can't get new gears for it.
The back cover plate is upside down. You need more lubricant in that axle as it lubes the bearings!
It will either be a H052 (3/4 ton) or H072 (1 ton). Only difference is in the brake drums and the gear set. It looks like a H052 to me with the smaller drum. As yours is coil spring that also points to H052. That means you PROBABLY have the 4.11 rear gear. They also made 5.13 and 4.56 (common). I've heard of a 3.90 (scarce as hens teeth), and a 3.38 (or something similar... I think this is a myth). Also heard of a 6.17, but I think that person confused this gear set with the Eaton H150 axle which is MUCH bigger.
So this axle will withstand a lot of power. It is reasonably light. However, you'll likely have to put up with whatever gears are already in it.
You can put a 14 bolt detroit locker inside the pumpkin. This is the strongest locker (or posi if you like) that you can get a hold of. Of course you can weld your spiders into a Lincoln locker if you prefer. If you get a 14 bolt locker, you'll have to buy correct length, 35 spline, 14 bolt axle shafts. You can buy some strong alloy axle shafts. You will have to bore the inside of the axle housing slightly to accept the new axle shafts. The 14 bolt axle flanges will bolt up to the Eaton hub perfectly.
This is a bullet proof setup.
New hub bearings / seals and new pinion bearings and seals will set you back a lot. Add to that the cost of a locker and new axles and it might be cheaper to buy yourself a 9" FxRD axle. Then you can get whatever gear set you want.
I have a 17 spline locker that will fit your axles, that I'll trade for a 3.90, 3.38, or 6.17 3'rd member if anyone has one and is willing to trade!
