Yes it is the same as your '00.

 

OK...so not one bolt but 3. I drained it again today as I had a hunch there was another. Sure enough, 2 more. Same numbers on them, same exact sheer.
Considering they are all clean sheers, and looking at the video posted I'm suppose they are one of maybe 8 or so on the inside there. My question is... how and why? If there are 8 or so all the way around it, how would 3 sheer off in a clean way, and the others would remain in tact? Also, what kind of trauma would the truck have needed to cause those?
I know zero about diffs, never cracked one open or looked inside. At this point, I'm not going to open it up as it would do me no good. I would not know what to get and I would have no idea what to do with it. I figure it was going for a long time like that, and there is no noise, vibration, binding, etc. Also, no other metal bits or shavings in the fluid. I have new and clean fluid in there now, so that at least in a plus. The other 2 diffs the fluid was fine, nothing odd and no metal.
If anyone has seen this, or might know a cause, please let me know. If this is an easy DIY and I know what I would be doing, I would be willing to give it a go. Otherwise, I'm sure it would not be that bad to find a 4WD shop to do whatever job it is. Opening/removing the diff just doesn't look that easy to me right now.

 

If people could tell me there is a good reason to swap, and that it is a fairly straightforward no special tools needed job, I might swap them. But I just don't know if I want to put a diff with double the miles and 4 years older in, especially being I have no noticeable issues with the current one.

 

Like I said before, I'd leave well enough alone.
No problems, you have no idea how long its been that way and it could be that at the factory the first diff they were installing had the sheered bolts, the heads dropped into the housing and they said eff it, pulled that one out and installed a new one leaving the bolt heads in the housing.

It is a pretty straight forward job, half a day in your garage.
Unhook the propshaft, remove the hubs, slide the axle shafts out part way, unbolt diff, drop diff on chest.
Inspect for sheered bolts, which you cant do anything with anyway because how do you get the bolts out that you cant grab?

Think about this, for anything to come in contact with the bolts and sheer them off the diff would have to be replaced anyway, nothing moves in there, I mean the gears move but thats it, they only go in a straight line, round and round, if they moved from side to side yes they could sheer the bolts I suppose but then the whole thing would be bad and need to be replaced.
So it is possible that your diff was replaced at one point for whatever reason and the bolt heads were just laying there, you only got one out your first time.

If you open it up in my opinion you are looking at ship fitters disease,you'll wind up replacing more parts than you thought you needed to.

 

I'm with you Spike. Lets see what happens. I think I do more harm to both the truck and myself worrying about crap like this honestly. I did most of the fluids, did the trans filter, did the throttle body heater, etc. She drove like new when I got it, and now I'm worrying about everything.

 

So, what happens the next time you are a couple hundred miles from home, like on a trail and your diff blows, now you have a tow bill that will bust your piggy bank.
You need to open it up, hell, not even a bad mechanic would have left 4 sheared off bolts laying in the bottom of the case while working on it in the past, you are about to have a failure.

 

I doubt these bolts sheered off last week. Chances are that they have been like this for a long time, and it will probably continue to hold up for many years and many moe miles. I would be on the "leave well enough alone" wagon too if it werent for the gear oil being way darker in the front diff than in the rear. That to me suggests a problem. Something is getting way hotter than it should, which will lead to a failure sooner or later. Question is "How much later?" How long do you plan on keeping this truck? I plan on being buried in my Disco (Without the 3 Amigos)

I would repair it, but like I said, I plan on being buried in my Disco. No hurry, just be shopping around for a good deal and get it done as cheap as possible. If I were the type of person that trades cars every 3 or 4 years I would not fix it.

 

IMHO time to BOLO (be on look out) for a diff from a young one in the boneyard. If 50% of the bolt heads are sheared, you don't know if that is every other one, or all in two adjacent quadrants, and continued use will be possible for a time known only to the Rover gods. Perhaps they have noticed that the ashes on your backyard meat roasting assembly have been too cold for too long.....

Thise are likely the ?crown bolts" - see attached, they torque to 58nm. The RAVE for a 95 Range Rover (similar) sows the attached diagram, and if you read what is involved with internal repair, replacement of whole assembly is easier.

 

Having that many out would worry me a bit especially driving at highway speeds (lockup potential?). If it were me, assuming you have a CDL, I would take out the front driveshaft for now and start searching for a new diff. Not having the front driveshaft attached will take off some stress on it and avoid binding up any other parts of the drivetrain in case it did bind up.

 

I totally agree with above 2 posters, start looking for a used one now.

My front diff died on a trip home, I have AAA+ so was able to get it towed to my local rover repair shop but even so I had to spend a night in a crappy best western with a pissed off wife and because I couldn't really shop around for a used diff I had to pay whatever my local shop charged for one they had handy.