Sun Feb 17, 2019 8:23 am by cornbinder89
There are 4 or 5 bearings inside most diffs, 2 carrier bearing and 2 pinion bearing , all taper roller, and some have a spigot (or pocket) bearing to support the inner end of the pinion.
All require dis assembly of the diff and bearing splitters and a press to replace and re setting the preload and tooth contact pattern.
Unless you have some indication of a problem, (noise that changes power on to power off) or the unit sat full of muddy water, leave them be.
The thing that kills diff's more than anything is lack of lube. as long as the unit is run with the proper amount of oil, the bearings are bathed in a constant supply of fresh oil kicked up by the rotating ring gear.
Since IHC used a drop-out center section (hogs head, 3rd member or what ever name you want to call it)
Vendor supplied axles (Dana) were not this way. if there is a problem, it is easy to pull the center section and deliver it to a gear shop that has the tools and expertise to do the job.
Its not hard, but requires tools most don't have and either enough experience to set by feel, or the special tooling to set by the book.
axle bearings, sit way out at the end of the tubes, and are either greased or run in oil once it gets out there, they are much more likely to fail from lack of lube than the diff bearings.