I changed out my diff fluids yesterday, everything looked pretty tight and no sludge really in the fluid or signs of moisture. Only problem was that on the plug to the rear diff was a pretty decent chunk of metal. Not huge, but probably the size of a roofing nail. Is this okay or something I need to pull the cover and check?

 

Could just be a burr from manufactuing the truck. Probably first oil change. Any other shavings? if it looked clear, I wouldn't panic, but would still keep an eye on it...

 

At 54.000 miles, that would have been the second oil change. Do you have an extended warranty, if so take the piece of metal to your dealer ASAP. Metal shaving are expected to collect on the drain plug, the factory really cleans the cases out before they are assembled.
It is safe to say you have a problem starting to show up. Do you do much wheeling, this does speed up the wear on the factory diff?

 

A chunk is going to be either off the ring or pinion, probably not good and worth a look.

 

I really only do level 2-3 trails w/ my disco, nothing that taxes it too hard and rarely submersed in water or mud other than a creek crossing. The diff fluid was in pretty good shape compared to what I used to see in my jeep (did harder wheeling w/ that though). No shavings in either diff, only small amount ofgrayishsludgeon the magnet. I guess Mike's right, might as well let them look at it since it's under warranty so at least it's documented. They still haven't fixed my damn leak at the windshield post, so it's got to back in anyway. That's another story altogether, I think it's the windsheild seal.

 

Yeah, what is the outcome if they check it and determine it was 'abuse' vs normal? You get stuck with a bill I assume? The Ashcroft 'pegging' trick looks like something worth doing long-term, esp if you mess with final drive ratios.