Front and rear diffs - oil full of metal flake

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Originally Posted by andeck

To the OP,...

Mechanic said after replacement that it was in actual fact a bearing, even though I was positive the noise was a gear noise. It came in with slight throttle load, and barely any noise when off throttle. Just thought I’d let you know that it was said to be a bearing, in case yours doesn’t improve.

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Thanks for that feedback. As much as it's bad news. Mine manifests similarly to what you report and it sounds like bearings to me. Gear mesh is higher and "whiny", this is lower and "grumbly". I've also dosed with Nulon G70 as it can only do good (or nothing). Hopefully I can run it for a while before needing to fix it but we'll see.

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Originally Posted by scarry

G70 was the indicater.

Nulon G70 will reduce and sometimes eliminate gear whine.

But it will not reduce bearing noise

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Makes good sense...now!!

Good luck discoclax, hope the g70 provides a good reduction in noise and prolongs the diffs for you.

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Originally Posted by DiscoJeffster

Unquestionably it won’t hurt to change every oil every 10000km, but required??????? There’s a lot of indi scaremongering going on to drum up consistent work IMHO. After all, it’s not like unnecessary oil changes will result in a failure - quite the opposite, however I’m not convinced some of the km intervals mentioned are in the customer’s best back pocket interests.

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indi scare mongering??? what a bull**** statement
.... is that because the indi repairer actually gives info and or recommendations to their customers ??? as apposed to dealers that say nothing to their customers, like my last two engine change outs on Disco 3 tdv6s. The dealer did the timing belt change but didnt do the oil pump upgrade, so instead of indi "scare mongering" (and of course lining the indi's pocket) it cost the customer the price of an engine change.

I dont flap my fat mouth to my customers to line my pockets, it is done to give customers as much info as I can so they can make an informed decision. It would be a hell of a lot easier to say nothing, follow whatever service schedule and forget about them and their vehicle until I see it in another 20/30K.

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Originally Posted by Ean Austral

0.61 ltr in the front diff and 1.1ltrs in the rear , not sure oil has improved that much that such small amounts can handle the long service intervals.

When we wanted to get extended oil intervals on our trawlers we doubled the sump capacity of the engines and the manufacture was ok with this, as long as we used the oil they recommended. I don't think any machinery has ever suffered from having the oils changed too often , maybe the hip pocket suffers a little but worth the extra cost in my eyes

Cheers Ean

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This, and we've had this discussion in the past Ean!

OTR trucks get 100,000km on one full syn engine oil change (with used oil analysis) but the sumps are huge, and the same goes for their g/boxes and diffs, I think 400,000km with a full syn fluid in a diff but we're talking 22+ litres of fluid in one compartment.

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Originally Posted by DiscoClax

Shane, interesting numbers. I'll put my ignorance out here for all to see, but I thought that those sorts of iron concentrations were a bit on the high side? Wouldn't something closer to 100ppm (or at least <200ppm) be a better place to operate? Not my area of detailed knowledge so looking to learn something.

I'd hate to know what mine was. It'll likely be >1000ppm still after the oil change given the metal paste settled in the bottom... Front was a visibly a bit cloudy too, which means the moisture content was way above safe levels.

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Not really relevant but Fe can be funny, I've had relatively low Fe numbers in one sample but used to get a PQ index result too, this measures the total quantity of Fe and it was through the roof. A component had failed and the chunks were huge but the PPM was actually small.

IIRC you can also get elevated Fe when changing the brand/oil type on an initial fill in a diff.
I seem to remember my oil analyst mentioning that, and you will see the spike drop to a normal wear pattern on subsequent tests.
I think it was to do with the EP additives reacting with the asperites in mixed lube conditions during that initial 'laying down of the additives' phase.

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Originally Posted by DiscoClax

Can anyone help with best method to get to the front sump bolts? The rears will be fiddly but we'll get there, but the front had me scratching my head. I'm thinking a T40 1/4" bit and a ring spanner, but even then it'll be a pain...

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Presumably way too late but I used your suggestion on my D4 at the time although my brother drilled holes through the cross-member of his MY08 TDV8 RRS to provide direct access.