So I did end up tearing apart the rearend after changing the u joints didn't fix anything.
pulling the drain plug didn't look very good...
Mmmm 75w90 flavored ferrofluid..
put after I pulled the cover the differential it self looked good, but once I pulled the C-clips and pulled the axles out... oof.
I'm assuming the massive amount of "tilt" the bearings had in the cage was allowing them to ride on the edges creating the uneven wear.
these didn't look too great either, but some 1500 grit sand paper cleaned them up really well, aftermarket axles are definitely on the to buy list, along with new 3.73 gears
after pulling the axles I went ahead and dropped the diff, and oh jeez... whoever that guy was that installed the torsen had no idea what he was doing, way too much preload (just reused stock shims) and for some reason only the driver side bearing cap was tight... passenger side was almost finger tight.... and the bearings looked AWFUL.
Had to hunt down a shim kit because apparently no one keeps those in stock?
Jegs had them at the warehouse, but I didn't have time to get up there on saturday after I called... Autozone hub on broad SAID they had 2 in stock, and after waiting in line for like 30 minutes.... they said "we can't find them" eventually ended up at the Autozone on East Main right down the street from the old Jegs building. which THANKFULLY had 1 set in stock
overpaying of parts is my favorite thing to do.
AND I STILL HAD TO WORK ON IT ON SUNDAY because SOMEONE forgot to press the bearings ALL THE WAY on...
had to pull the cover, check the bearings, and reshim it on sunday...didn't take all that long to do, just annoying.
And after all that.... STILL MAKING A NOISE... or well it was on Monday on my way to work, today (wednesday) doesnt seem to be making any more noise than usual, but I am suspicious of the torque converter, about a week before the rattle started it was making a louder than normal knocking sound in neutral...which the transmission of torque converter has ALWAYS made, confirmed that in 2019 when I ran the engine without the torque converter unbolted. Transmission still shifts fine, all the gears work, doesn't flare, just always has what kinda sounds like rod knock.
Torque converter was replaced in 2019 with a "good" used one from a friend....but he did blow up that 4l60e.
Tuesday I turned the engine over 360* from the flexplate checking for cracks or loose bolts and saw nothing obvious, and since it is accompanied by a vibration I checked the misfire count/history and both were zero on all cylinders
if anyone thinks they might be able to help pinpoint the noise I got a pretty good clip of it monday night on my way home from work. audio was boosted a little to make it a little more pronounced, starts around 0:02-0:03