Hey folks - I'm the OP and I've got an update.
Got everything cleaned up, installed, and buttoned up. FYI - I make a mistake earlier: this diff calls for 75W-140, not 90W-140.
Anyways - for the most part - the truck is smooth when driving straight down the road, which makes me thing our pinion/ring setup is operating correctly.
When turning left or right, it very consistently makes a rythmic, gnashing sound that fades away after straightening out. Not too pronounced, but enough that we need a solution. Only very occasionally, this gnashing begins when driving straight, although it's not as pronounced and seems to fade faster.
So, I'm guessing that there was collateral damage somewhere in the worm wheel/spur gear.
I suppose my question is are these gears available to purchase/rebuild? I'm having trouble finding a source, which makes me think they're not and we're going fishing for a new rear-end.
A drag that we just missed Torsen's sale of those NOS units - my buddy would have jumped at the chance to own one for $325.
Any thoughts? I appreciate you guys!