Opening up the Differential - So, last weekend I finally opened up the differential and took a look inside. I drained the oil and inspected everything mentioned in this thread so far. I'll go through them all one by one...
- Cover - I checked the cover for any signs of something striking it, rubbing on it, etc. The good news, like most axles, the inside of the cover and the inside of the differential have been 'stained' with the oil for so many years that it's turned that darker color. Because of that, it makes it very easy to see if something is rubbing/striking as it will look more silver. The cover showed no signs of anything hitting, and the outside edge of the ring doesn't show any signs of scraping.
- Ring - As mentioned, no signs of scraping on the outside. I took very detailed photos of the ring during install, so I compared it now with my photos of it then, nothing seems to have changed.
- Carrier Ring Bolts/Lock Straps - I checked the bolts holding the ring to the carrier and the lock straps. No signs of them rubbing/striking the differential housing in any way. I can't see how it could be moved enough to strike as the carrier is in there nice and snug and there's at least a quarter of an inch or more of space between the bolts and the housing. But regardless, nothing looked scraped on the housing walls.
- Pinion - As with the ring gear, I used photos I had from install and inspected it. Could not find anything out of the ordinary.
- Spider Gears - Checked all four of the gears, no sign of wear.
- Axle shafts - Pulled out the axle shafts, no sign of abnormal wear on the ends interfacing with the spider gears.
- Carrier - Didn't see anything out of the ordinary with the carrier itself.
Axle Wedges - As mentioned a few pages back in this thread, some people were saying they felt the angle of the differential when I decelerate is moving downwards too much, possibly causing the pinion to move from stress. So, I went out and got a set of axle wedges to give it a try. At this point, I'm willing to try whatever. It was a process getting those in there. I used 4-degree wedges (about .4 of an inch). After installation and everything tightened down, I took the Jeep for a spin. The sound didn't change at all. Sigh.
Drums - Another item that I wanted to try, just to check a box off, was my drums since they have moved over from the original axle. The drums are replacement GPW ones I got from a friend after the drums that came with the first GPW axle were so far out of spec that you'd need to use thicker pads. So I got a set of GPW replacements for the rear axle that were well within spec. As you might recall, to make sure with these replacements, I recently took them in and had them resurfaced with no change in the sound. So, I grabbed one of the original out-of-spec drums and decided to install one of them (with different bearings/races) on the axle one at a time. This way, I'd still have 3 wheels that would brake. Tried the out-of-spec drum on both sides, no change. It was a long shot, but gotta check everything off. So the good set is back on the Jeep.
New Yoke - Another item mentioned was that possibly my yoke is worn out since that is another item that's traveled from the first axle to the second axle. It's been a bit of a pain finding a good yoke. All the repro yokes you can get online are modern versions that look nothing like the WW2 ones, and at about $45+, I'm not going to spend that much just to test a yoke that I won't use. So, a week ago I won a good condition yoke on eBay (take-off). Sadly, it's been a week and the seller hasn't shipped it yet. I'm hopeful it will ship soon after I sent him a message yesterday asking for a status update. Once I get that, I'll swap yokes (and check the pinion pre-load again).
So, that's where I am now. Pretty much back to square one. I did take the Jeep for a drive to the Planes of Fame Air Museum at Chino Airport, CA (I'm a photographer/social media creator for the museum) yesterday and she ran just fine, though it was VERY hard to tune out that clackity sound the entire 30-minute drive there and back. I was hyper-aware of any weird sounds, vibrations, etc worried that something was going to go wrong. But thankfully, nothing did.