ID a old rear end/ differential

IIRC yellow charges the system, red is trailer brakes and blue is the truck brakes.

 

These were good old horses, Rockwell is a dynamite rear axle, should be a tag saying ratio, in that truck, speed limit was 55, so I bet they are 4:11, top out about 72? The blue brake, some were black, I believe just sets the tractor brakes, rather than yellow exhausting the whole magila. $4grand? The motor/trans is worth that. Them old FLs with the clutch through the floor were cold in winter, and the doors never seemed to close right and I wouldn't recommend the aluminum frame for logs. Sounds heavy. I'm sure plenty did, but I knew several with aluminum frames experienced cracks, ended up lining them with a steel channel. For that money, I'd go for it anyway. They were great trucks.

 

What axle shafts does it have. Small diameter 12 bolts or large 8 bolt? White Motors and FL used the 12 bolts mostly on their stuff. Majority of those were spoke wheel hubs but many were budd hubs. All the big trucks back then had the Rockwells. Tough. They grunted a lot of iron across the continent and still do. They are still out there. The SQHP’s had an oil pump and filter on front diff. They were good for 50,000 easy. The ones you have can take 44-46 easy. Lot of old timers put them through the test daily in those days.

 

The 12 bolt axles are just as tough but parts are much harder to find. They were very common in those days but not anymore so many parts are not on the shelf for them.