@Keith_L : You mentioned a possible bent axle housing. That was also mentioned in a RELATED THREAD from the 4th gen forum, shown at the bottom of this thread, where the OP's issue/symptom was a grooved axle shaft and the shop found a bent housing.

By "axle housing" do you mean the tube that the axle shaft "lives" in? And what's the best way to diagnose - just crawl under and eyeball it and compare it to the passenger side?

 

Yeah, if the tubes are not in the same plane, puts odd loads on the axles. You won't be able to just eyeball it.... unless it is REALLY bent.

 

Hmm. While I have both axle shafts out, I did look down the barrel and I could see straight on through to the other side.

I guess since I don't see anything obvious, especially if I can get a couple of OEM junkyard shafts for the price of one cheap new one (don't know yet - will have to see this week), I guess I'll just clean it all up, put it all back together and see what happens. If I end up with another issue on that side in the near future I'll take it somewhere for the pros to look at it.

How would a shop determine there is a bend far enough to affect the load but not far enough to eyeball?

 

Mittler Bros makes an alignment tool

I suppose you could just put a good angle finder on each tube, they should be basically identical

Do you get any gear oil leaks from where the tubes press into the pig?

edit: an angle finder wouldn't show fore/aft bend but you might be able to lay a straight edge on the pinion yoke or flange and measure to each tube. This wouldn't be exact but I'd think you'd see a trending increasing or decreasing distance, even with a tape

 

Temporary overload with a bit of oil starvation will discolor or spall the axle enough to start the axle groove, might take awhile, could be on the prior owner. The amount of oil to the outer bearing on these axles can be skimpy, LSDs seem worse.
If you can measure axle housing bend with your HomeDepot tape, you are past the point. Axle builders measure them on a bench in a jig with decent tools. All you will measure, laying on your back with axle in the truck, is your own error. Reasonably tough to bend a housing.
I have swapped a 2001 axle into a 2003 housing. Posted about it here somewhere, stuck on side of road kind of thing. Axles will swap, be aware, 2002 and up axles use 9/16 studs vs. 2001 down 1/2. Why rims are listed differently.

 

Exactly, if it is a bend that caused this groove I think it'll be detectable with basic tools. If you can't find evidence of a bend, throw in a new shaft, bushing and seal and see what happens...

 

Yeah, I agree with 69 here. I would more suspect low fluid, and the bearing eating the axle before much of anything else. Replace the axle, bearing, and seal, clean everything up nice, and call it a day. Just make SURE you have enough fluid in the diff.

 

I must confess that this issue was not caused by the prior owner. It is a combination of my ignorance, procrastination, busy-ness and stinginess and distrust frugality (among other things).

So yesterday afternoon I went to the local LKQ PYP (my first time to any junkyard in nearly 30 years) without power tools, and after MUCH consternation and MacGyvering, I came home with two (seemingly) good axle shafts, a differential cover (mine has a gash in it), a stock jack "kit" (tire tool and extension rods), and four sun visor clips, all for less than the price of one of the mid-grade/mid-priced new axle shafts on RockAuto. (I would have tried to get more "stuff" from the handful of 2nd gen Rams they had, but I didn't get there and inside until nearly 2:30pm, and with all the trouble I had it was ~4:30 before I had the axle shafts in hand, and I was hot, thirsty and very tired so only grabbed the visor clips from a couple of them.)

Sometime in the next few days I intend to clean up/out the inside of my entire rear axle, install the new bearings and seals, two good axle shafts, new brake shoes, "new" differential cover and fill her with AMSOIL.

Thanks for all the help. I wouldn't be at this point without it!

 

How was it your fault? Are you saying you just let the diff get too low on fluid?

Whatever it was, *I* am certainly not gonna mock you. I'm sitting on at least a couple projects that could be much more costly if I keep procrastinating but I just never seem to have the time. For one, I need to do a complete timing set on my wife's 3V Ford, but that's likely 4 solid days at MY pace....

 

...plus driving with an unidentified noise (which for the longest time I thought was coming from the front - which doesn't excuse not diagnosing it promptly). I've done and am comfortable with a decent amount of engine work, but I know nothing of transmissions and knew nothing of differentials/axles.

So add to that: my lack of desire to fork out way more money for something I can do myself for less + not knowing whether I could really do the work myself + my general distrust of mechanic shops I don't know + my last couple of dealings with the shop I had trusted + the infrequency the truck was being driven + work & family busyness.

All that equals not doing what needed doing when it needed doing.

----
For the record, no one was mocking me (that I am aware of), and no one poked at me (which I can completely take if they did). But in @69_XS29L 's excellent addition to this thread, he stated:
I couldn't, in good conscience, let that go without correction via confession.