I purchased my 2004 Disco 2 about ten months ago and have been steadily making upgrades and improvements but one issue has persisted since I made the purchase and I'm hoping for some direction in properly diagnosing and resolving, ideally without fully replacing my rear differential should that be the culprit.

Symptom: "clicking" or "clacking" at engine speed from the rear of the vehicle most notable after removing foot from accelerator and/or coasting. Metal shavings in rear diff gear oil as picture below.



What I have done thus far:

-The PO installed a ~2" lift to the vehicle but was still running stock driveshafts and the rear rubber flange. I do not know for how long he was running this setup. I have replaced both driveshafts with Tom Woods and deleted the roto-flex to accommodate the 4-bolt flange a Tom Woods requires.

-Changed gear oil in T case and both diffs immediately upon taking ownership of the Disco and again about 6,000 miles later, after the roto-flex delete. The photo from above was taken during the second fluid change, so after the flange swap.

-Given the shavings in the rear diff fluid, I doubt engine/T case mounts are the culprit but some are indeed split so I've ordered a full set of replacements from Lucky8 and plan on doing that swap as soon as they arrive.

I'm new to 4x4 vehicles (ones actually worth working on, at least) and have zero experience with differentials so I'm hoping for some advise on what my next steps should be and possible solutions. I asked a supposedly knowledgeable friend about this shortly after buying the vehicle and his response was "meh, probably the pinion flange. Just drive it. Should be fine for awhile." Seeing how this could be a potentially serious problem and the Disco is my daily, I'd like to get this resolved during the warmer months here in New England so I can ride my motorcycle if the Disco is out of commission for a bit. The symptoms do seem to be getting worse.

Any advise is greatly appreciated! Thanks!

 

I’m not the diff expert, but that’s a lot of metal on your plug. I’m pretty sure the Rotoflex drive shaft was not the cause. It’s supposed to be okay up to a 3” list. At any rate, I think it would only cause the driveshaft to wear sooner, but I don’t think it would harm the diff itself.

 

I would drop the pumpkin and have a look, my guess is you have a bearing going out. Pull the hubs on the ends, pull the axles out, and pull the diff. Look for loose bearings in the diff. You may want to source a spare pumpkin from a local breaker.

 

Thanks for the reply. Like I said, I'm new to differential work so pardon my ignorance.

Are you basing this assessment off the shavings on the drain plug?

I'm assuming by "spare pumpkin" you're suggesting I find an entire differential assembly? Rovers North has used assemblies for ~$450 (https://www.roversnorth.com/parts/ft...isco_i_ii_rear) but we're hoping I might find a better deal at a local scrapyard? I'm in a fairly rural area of Maine with few options for scrapyards and would be hesitant to risk an eBay purchase, though used assemblies can be found for about half of what Rover North is asking. If I'm picking up on what you're saying, it might be cheaper to just replace the whole unit in one go and tinker and fix the current assembly on the bench at my own pace? This would allow for the learning curve as I grapple with the ins and outs of what seems like a rather daunting task, judging by the RAVE instructions, and I'd have a spare diff in the end?

Are there any other methods to narrow down possibilities here or am I pretty much at a point where I need to get a look inside the whole thing? I didn't buy the Disco so I could shy away from the tasks of keeping it on the road but just so ignorant about differentials I don't even know how to know if I'm heading down the right path and none of my research around differentials is consistent with the "clicking" or "clunking" at wheel speed I'm noticing. No whining or gear grinding sounds. I've been using 75-90 synthetic gear oil.

Thanks again!

 

You can rebuild the diff yourself, but why don't you watch some Utube vids on how to do it first. By the time you buy all the bearings and shims and maybe new R n P, and tools, and learn how to do it correctly, you might as well just get a used one. I found a couple of good used ones off ebay for < than 150 each shipped.

 

This Also, have you even looked for someone breaking one in your neck of the woods? FB marketplace? Usually these are being broken all over the place. Just put a search on and let it run. As far as the clicking sound goes, one thing to consider testing is put the rear axle on jackstands and let it roll in drive, see if you can hear and pinpoint the clicking (be safe, front wheels chocked, 2nd set of jackstands under the frame, don't get in front of the wheels - or take it to a shop who can put it on a lift and get under it with the wheels turning). Have you pulled the DS to make sure its not just a worn ujoint?

 

Awesome. Sounds like we're in agreement here. I'll start looking around the local forums anyhow. I've seen some D1's as parts vehicles but no D2's as of yet.
I'll lift up the truck in some fashion to try and isolate. I have pulled and replaced both DSs, one right after another, and drove for a bit with just rear and just the front installed trying to isolate the issue. My first attempt at the fix was U joints. So now I've got all new Tom Woods so that ain't it. Engine mounts are arriving this week so that's the next last option before doing a used rear diff assembly and given the shavings in the oil I'll likely do that regardless. I'm happy so long as it doesn't go out on me in winter.


Thanks XRAD!

 

I finally have an update on this issue. Life outside the Disco along with sourcing parts delayed things a bit longer than I'd hoped but I followed your advise. I sourced a used diff off ebay for about $130 with shipping (along with a whole new rear brake setup while I have the axle in pieces).

Turns out the bearings look fine. The cross shaft in the spider gear group sheered in half. I'm not sure if one of the roll pins securing failed first or what but this is what we're dealing with:





As you might can see from my photos, there's damage to the inner radius of the crown wheel splines as well as the so called "planet" and "sun" gears. Obviously the carrier is toast too. Given this, I'm assuming a total loss of the differential unit here. Please correct me if I'm wrong but based on a cursory pricing of the individual gears I'd quickly get very near the price of a new replacement unit. Kind of a bummer as I was looking forward to learning the overhaul. No tears though. I have other means of having fun.

One thing of note is the difference between the damaged differential and the used replacement sourced off ebay. Mine is 2004 D2 and the markings on the bearing caps indicate (I'm assuming here) a manufacture year of 2003:




The replacement reads thus, and therefore I assume it's from a '98 model produced in 1997:




I'm kicking myself for not taking a couple photos of the gearing in the '97 example but time was a factor and I just needed to get it installed. I noticed the cross shaft is significantly smaller in diameter than the '04, about a third smaller I'd wager, and is retained via two c-clips rather than roll pins. Given the larger cross shaft sheered clean in half (granted it took about 19 years to happen), I'm curious to see how long this even older example lasts. Do either of you have any knowledge or preference in this design change for the '04 models?

One final question: All of my research leading up to this indicated there's no difference between the front and rear diffs apart from the 3-hole vs 4-hole flange. I'd already performed the roto-flex delete so when sourcing a replacement diff I settled on one with a square four bolt flange thinking it's plug and play with my Tom Woods driveshaft. Now, after the swap has been completed, I notice in the rave it mentions on page 51-10:"NOTE: Older front differentials have a square flange and an extra spacer fitted, this spacer must be removed. Later front differentials have a round flange but no spacer fitted."
I'm wondering if that's what I got. The RAVE isn't specific of model years qualifying as "older." Perhaps there are some clues in the markings photoed above? If need be I could always pull the flange off my broken diff and swap that but I'd really prefer not.

Hopefully I'm shored up for a bit. My backup vehicle is now on the mend so I'm needing to get the D2 rolling again. Any advise or assurances is, as always, greatly appreciated.

Thanks for your help fellas!