So, before selling your ride, lets get some more info. Under what does turning left or right make the problem better/worse? Going over bumps/dips? Or is it strictly while moving forward? Does it do it in reverse?

Did you ever change the front diff fluid per your original post? Any metal chunks?

There is a rubber coupling on the rear driveshaft at the rear diff (Rotoflex). Have you given that a once over?

 

yeah, my wife wants to me sell it... but at worst, i'll probably just get a 'second' car to have a backup. I'm too attached to my Disco and i doubt i'd get enough to make it worth my while to actually sell...

As for your questions:
- turning has no noticeable effects
- going over bumps (i hit two pretty rough railroad tracks on my commute to work each day, and on the way back) has no noticeable difference.
- it seems to be strictly while moving forward, though when i back up my driveway (about a 25-30 degree slope) there occasionally seems to be a 'slip' where it feels like the wheel just isn't grabbing or something. But it's only done it twice and i wasn't really looking for it to happen at either time so it's tough to say exactly what it was.
- i did not get around to changing the diff fluid this weekend, i concentrated on the drive shaft, but the diff fluid is on my radar for this week (time permitting).
- i have not looked at the rear drive shaft at all; never even really thought about it since the feeling seems to be isolated to the front passenger side.

 

Yeah, you may have a bad wheel bearing.
Not hard to change on a D1.
Not sure about the D2.

If the RACE is not damaged, just put in new bearing part and see how it goes.
Grease it well.

Wheel bearings will thump / grind around certain corners that are tight - but not all the time.

 

On the DII - Bearings are not replaceable separately - You have to replace the entire sealed hub assembly... Not a cheap repair...

 

right, the only place i've found the hub assembly so far is Atlantic British... and it's like $400...

 

I seem to remember somebody found some chinese hub assemblies that were much cheaper.

But knocking isn't a normal sign of bearing wear unless it is extremely worn.

I guess another possibility is the passenger side CV joint. I still sorta wonder if something isn't loose under there.

 

Mind a hot exhaust, but try jerking the driveshafts left/right, up/down with them on the vehicle. Shouldn't move at all. I'm still on it being somehow related to one or both shafts/flanges. My experience with bearings and diffs is that it changes with direction (turning) and loads on the hubs/gears. Did the flange on the transfer case with the bolts have any play while you were fiddling with the front shaft? Perhaps the rear output on the transfer case?

 

one thing i noticed on the drive home (mind you it was raining so i couldn't hear much) was that when i make a HARD right turn i hear a 'whine' - but that doesn't happen when i make a hard left.

... and i don't see myself getting a chance to do much more work on it until at least Wednesday night, going to be a busy couple of days at work...

 

Then my next recommendation would be to change your front diff (1st) and TC (2nd) fluids, looking for excess shavings or chunks of metal. If all looks good take it for a ride. If no metal comes out, it's probably a bearing if new fluids don't help. Give them another once over. Others will likely chime in with more info.

 

If you need hubs, they're on ebay for $106 shipped.