NORMAL?!

I have some serious grinding and some less serious vibration in my front somewhere. I was trying to figure out my stock gearing for the front of my '99 with NP231 tcase. I thought it was maybe a pinion or carrier bearing so I was going to drop the front ds and drive to see if the noise is still there. When I tried to mess with the front ds, I could actually twist it partially back and forth. There is a clunking in the front pumpkin when I do so. Is this normal? Could it be something in the tcase and not the front diff? I have a lead on a donor d30 axle--so I can swap another in. Help!

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I would start by dropping the front ds and checking the fluid in the front diff. Look for burnt fluid or metal.

Sorry...1999 XJ with 4.0, AW4, NP231 tcase, 130K on the clock, stock height, shackles in the back.

dropped the front drive shaft, lubed up the slide fitting. I changed the diff fluid and it was a little on the burnt side with some metal flecks. However, there was a lot of backlash---more than the alloted some-odd thousanths. I don't have a dial-indicator. The carrier bearings don't seem in bad shape and the pinion was pretty solid--no play. The only thing is there was a lot of backlash. The grinding noise is still there--would too much backlash be the cause of a constant low-level grinding noise? The unit bearings looked fine; I gave the spin and 12 o clock/6 o clock shake test. No shimmy. I drove it around with no front ds and it still makes noise. What is the source of this damn grinding?!

If there are metal flecks in the grease, the ring & pinion are toast. I had a rear go on an F350 awhile back, first the pinion seal went, then the grease ran out, then it started whining under load. Tried to add grease, poured it in the back and watched it run out the front. Pulled the rear, sent it to have a new gear set installed.

Mark