Wonder what happened to this bearing?

[4WD]

Used it too much when it was new …

 

[4WD]

Not that great of a picture to make a judgment, but if it were mine...

Looks like low lube film, high loads, and mis-alignment or loose setting.

I would replace the bearing (obviously), go a step or two thicker on my lube selection, and error on the tighter end of the setting range tolerance. Maybe look and see if there is a P900 version of the bearing size you are using. That adds a feature to the rollers that makes them less likely to suffer from edge loading.

I was a Timken Engineer for the first 5 years of my career.

Well - you have likely seen rare failures like I did - D44 that had lube changed at 30K and at 62K fully failed.
Bearings, ring, pinion, pins, spiders etc - All looked cold rolled and not heat checked … would have thought it had hydraulic fluid (thinned out 140 Pennzoil) if not for the smell …

 

[PontiacHO]

Your statement seems to contradict itself a bit...

If it is a shimmed assembly, then that shims should do the setting of the bearing pair, and the nut is used simply to snug things up, and does not effect bearing setting (neither preload or endplay). With out knowing if the bearing pair is direct mount, or indirect mount, and where the shim pack is, I can't tell you if the shim pack will tighten the setting or loosen the setting.

If the assembly is set with the nut through rolling torque and backing off, then the shim pack does nothing for the setting of the bearing pair. The setting is determined simply by the stack up through the position of the nut you are adjusting.

I was speaking of Carrier bearings…not pinion bearings that are indeed preloaded with pinion nut. The pinion depth is set with a shim but not the preload. Carrier bearing preload is set with shims (Salisbury differential) to include the ring and pinion backlash. Hotckiss differentials typically have spanner nuts to adjust carrier bearing preload and ring and pinion backlash.

 

[SwampSurvivor]

The carrier bearing races on my very failed dana 30 looked like that. Well, the last time I was in it before it completely gave out. I would gess in the case of mine it was from sitting with crappy fluid for a while. Water, coal dust, etc.

When I was in it April of 2021 I noted that the carrier bearings were done and it was time for a rebuilt. When we pulled it apart to rebuild in September we could see that the carrier bearings started to spin in the race !