Yesterday I found a pair of axles from a super duty, leaf sprung, 3.73, "J2R43" stamped on top of left knuckle, rear axle has disks, came from a V10 truck. I'd like to know if this is a D50 or D60. I know I should have rolled it back and gotten all of the # off of the tag and looked at the front cover, but I was hot, tired, and they were sitting in the bed of a truck underneath a V10. I know these are a bitch to put in a EB or other little rig, but how do they fit under a full size ford? Thanks in advance.

If they are out of a SD SRW the front axle will be a D50, rear will be a Sterling 10.5. If the rear axle has both of the calipers on the back side of the axle then it is a late 99+. The early 99 had one caliper on the front and the other caliper on the rear of the axle. IIRC all DRW and the 03+SRW F350 has the D60 front. Front axles all have unit style wheel bearings, they are not serviceable. I have seen them last only 40k and as much as 200k. The bearings run about $230/ea.

You should know the front D50 has a habit of snapping pinion shafts since it uses the same small pinion shaft and yoke as the D30 & D44.

I forgot about the sealed bearings, definately not going to work with my diesel and 37s combo. I might pick them up if the price is right and save them for a lighter rig.

'02+ SDs have a D60 front. The sealed bearings and the metric bolt pattern make them less desirable than the earlier stuff.

You should know the front D50 has a habit of snapping pinion shafts since it uses the same small pinion shaft and yoke as the D30 & D44.
This is simply not a true statement.
Sure someone might have broken a D50 pinion shaft, but then again pinions on every diff ever made have been broken. But IMO the D50 has held up well in Diesel drag racing and truck pulling. The axle shafts have been the weak link and only in diffs that were locked, and following a catastrophic rear axle failure causing all the engine power to transfer to the front. As far as the unit bearings go you will need some old axles to avoid them no matter whose axle. 99+ SD Ford 4x4 all use them, all the 4x4 IFS GM 1/2-1ton pickups have unit bearings, The Dodge 1/2-1 ton 4x4 second generation on up all have the unit bearings as well. Dyna Trac does offer a bearing retro kit to change to serviceable bearings.

This is simply not a true statement.
Sure someone might have broken a D50 pinion shaft, but then again pinions on every diff ever made have been broken. But IMO the D50 has held up well in Diesel drag racing and truck pulling. The axle shafts have been the weak link and only in diffs that were locked, and following a catastrophic rear axle failure causing all the engine power to transfer to the front. As far as the unit bearings go you will need some old axles to avoid them no matter whose axle. 99+ SD Ford 4x4 all use them, all the 4x4 IFS GM 1/2-1ton pickups have unit bearings, The Dodge 1/2-1 ton 4x4 second generation on up all have the unit bearings as well. Dyna Trac does offer a bearing retro kit to change to serviceable bearings.

I'm not really worried about tearing up front pinions and front shafts, the truck wont see much 4wd use. I liked them for the front and rear disks, the diesel friendly gears, and crossover steering, plus I can get used metric pattern wheels cheap. I do plan on running alot of miles with big tires, and don't want to pay to replace wheel bearings and $200 a side, but I'll snag the axles if the price is right, and sit on them for a 1/2ton or EB project.