Got into changing my rear differential fluid today and saw the holes worn through the (what part?), and so obviously I have some serious problems here.
According to my build sheet I have a 10.5" anti-spin differential on a 2005 Ram 2500 5.7L 4x4.
Also according to the sheet, I have 3.73 gears, but in the service manual for my 05 2500, it says the gearing can be 3.21, 3.55, or 3.92 ..... 3.73 isn't listed as an option.

At any rate, what replacement parts do I need to look for? I have no idea where to start here.

 

ummmmmm.......so at Mopar Parts Canada they have the part listed there and it looks like THIS!!
So, there's actually nothing wrong with my rear end?

 

that is the differential case.
with metal going thru the diff...the side and pinion bearings are probably nfg. a close inspection of the crown and pinion gear and housing is also a good idea. some third gens had a rear diff recall for a loose pinion nut. see if yours is in the recall. if yes and the pinion nut is loose...it may qualify for a rebuild.

 

ya but did you see the picture I posted above with the same part (presumably new) from Mopar Parts Canada? it looks the same.

I also checked the Mopar website, there wasn't a recall listed for the differential at all.

 

Old and new look suspiciously the same to me. If there isn't excessive amounts of filings in the fluid, and no visible damage to anything in there, my take on it would be to button it up, and refill with fluid.

 

That's exactly what I did. Everything looked ok, the only reason I really thought something was wrong was because there was a little chip from the machining that just broke right off, it wasn't interfering with anything so it seemed to me like something bad had happened.

Apparently this is how they normally look and maybe whoever cleaned it up (15 years ago) at the factory didn't do such a good job.

Everything is working fine and after changing the fluid my shudder when turning corners went away..... I knew what that problem was though, that's why I changed my fluids.

 

If you're differential needs repair you'll know it! Grinding and clunking will be painfully obvious. Make sure you clean the magnet every time you go in there.