Thread: Front and rear diffs - oil full of metal flake

Originally Posted by kenl

For what it's worth I don't think that you can check the oil level on the the D4 diffs, you can only drain and refill with the correct amount of oil. That is how it reads in the manual anyways, I have not changed my own diff oil yet.

Most just fill them until the oil just starts to run out,with no issues at all.My Indie has been doing it this way since the D3 arrived.

As for testing the diff oils,very difficult unless quite a quantity is removed into something like a glass jar.

Just seeing what it is like on the end of a finger is just real guesswork that doesn't give much of a result,unless the oil is like treacle.

I found with the D2 the rear diff oil was always in worse condition than the front,which i presumed was because it did more work than the front,but maybe i was wrong.I haven't checked the D4 diff oils as it is serviced by my Indie.

Originally Posted by garrycol

Well yes and no - in the D3/D4/RRS unless you go to a lot of trouble it is not really feasible to check the levels of the diffs etc as they are not fill till the filler overflows. You drain and refill with the specified amount of oil.

Also at the distance covered by the OP the diff oils are not on the serviceing schedule for the car so unless the owner had instructed such work it will not be done if the work is at a dealership.

On my car I have noticed that putting in the correct amount of oil is close to the bottom of the filler anyway so I just fill like the old rover diff and fill until it overflows and I guess it is only about an extra 20ml for the front and about 30ml for the rear and has not caused issues.

But the point is that right or wrong the OPs car as far as the diffs are concerned, were serviced in accordance with the schedule - that is, no action required at that point of time. Probably only got a visual inspection on the hoist for leaks.

Garry

Seriously, How hard can it be to undo the filler plug and dip the oil to have a look at it whilst the truck is up on the hoist especially with these extended service intervals???
It would maybe add another 5min to the service times which in all honesty are pretty well "Padded" and leave Plenty of time to do this.
It's Not all about what the service schedule dictates, It's more about just how good and thorough the workshop is when they service your vehicle Because as far as I am concerned fault finding and quickly checking out the rest of the vehicle should all be part of a service.

Originally Posted by trout1105

Seriously, How hard can it be to undo the filler plug and dip the oil to have a look at it whilst the truck is up on the hoist especially with these extended service intervals???
It would maybe add another 5min to the service times which in all honesty are pretty well "Padded" and leave Plenty of time to do this.
It's Not all about what the service schedule dictates, It's more about just how good and thorough the workshop is when they service your vehicle Because as far as I am concerned fault finding and quickly checking out the rest of the vehicle should all be part of a service.

If you believe that 9/10 workshops do that you’re kidding yourself.

If there’s no signs of leaks, and there’s no obvious signs of wading I doubt they even give it more than a visual - unless specifically requested to do so.

As your very own words stated “quickly checking”... if there’s no signs of leaks there should theoretically be no loss of oil. And with the fill to volume rather than fill to overflow method it’s more difficult to get to the oil.

What a “dip and inspect” also won’t show is any solids settled into the bottom of the diff, gearbox etc..

Originally Posted by trout1105

I have no doubt that regular oil testing in aircraft engines is a critical safety issue and also a financial issue as well But I do find it hard to justify the time and expense to get these test done on a run of the mill car/4WD.
What the real issue here is the extended mileage/time between services on the newer vehicles AND the "Quality" of that dealer services.
Even if the oils are not to be changed at a particular service a "Competent" dealership would at least check the fluid/oil levels and physically check the condition of those fluids/oils.
As in the OP's case this was obviously not done or even worse the condition of the oil in his diffs was simply ignored on prior services.

I'll let you know why I do oil testing:
1) it's part of my job at work so I am interested in the subject anyway
2) extend oil change intervals or shorten as required. Oil waste is an environmental issue so I do like to minimise it where possible
3) trending of oil condition and wear particles for condition based service/repair rather than scheduled servicing. I've had one failed auto trans and I'd prefer not to have an unexpected failure like that again if possible (even with another big failure it will be better if I get a little warning to prepare for it). So yes it would cost me a little more, but also for example the auto trans oil - I've never used oil before that's as expensive as this stuff so I'm happy to change it out on condition (like I said previously I don't run it to the ground as there is always a buffer left).

Anyway whilst I don't know for sure, I would think most vehicle manufacturers would be testing oils during development - with extended oil change intervals that are increasingly common they will be covering there own arse to ensure that the intervals are not going to create any warranty issues down the track.

Hmm,, a bit late to the party,, but anyway

DiscoClax, being in the industry yourself, you'll be fully aware of the pitfalls of swarf in the trans, diffs etc. A human hair of approx .08 mm at just 3 mm's long can destroy a bearing apparently so whats steel swarf going to do(?). Flushing them a couple of times should give you more longevity out of them regardless.

So, a little story, I hope it can help someone.

I used to manufacture gearboxes from start to finish, (I have worked in every aspect/area). That is, I/we turn down parts, heat treat said parts, perhaps then grind to size depending on part, deburring, (both mechanically and manually), is done at several intervals as well, clean at every interval and assemble to a finished product.
I can tell you all, that during this entire process, the cleaning is of utmost importance at every cycle/process, and is usually done via "Hot Wash". To look at these parts, they are absolutely spotless coming out of the wash.
Upon assembly, the second last process of the entire build is a dyno run. This fills the trans with oil and cycles it through its paces to see how it operates and finds any faults. Leakage and shift qualities are presented and problems can be found with both components and/or assembly procedures. If faults are found, trans is sent to "Re-workers" to find and fix said faults, then gets retested again.
However, when you see the crap that comes out of a brand new just built trans, it would blow you away. Parts that were spotless when they hit the assembly line, after dyno, to the untrained eye, it looks like a train wreck has just happened inside the main transmission case.
Trans then has its own filter placed in, and "buttoned up" and packed up.

Interestingly, at the time, we were the ONLY company manufacturing transmissions to do a "wet test". Other companies just test for leakage etc by air/gas/vacuum testing. So then this makes one wonder how clean the trans is when delivered by them, or for that matter, any assembly,, ie; diffs etc.

Now, I no longer do that line of work. The company moved OS, but I did finish my career with them in the R&R center in Melb, which showed another insight into transmissions. Like you DC, I got to destroy lots, testing gear quality, oils etc in an effort to save money. Yes cars can last a long time, oils are far better now than they used to be, but the change intervals they suggest seem to be way out,,, especially if they've not been wet tested.

Strangely, I find changing recommended oils a bit of a worry. Maybe Rick could be called in on this, he's a bit of an expert on this subject. But from my own perspective/experience, having done oil trials, its not a path I'll ever go down again. Oils are made up of several components for a reason. Change one component by say just 1%, can change the entire outcome of a trans' lifespan. This applies to manual gear boxes too. Some metals are designed to absorb oils to help with lubrication/life span. Change that, and the metal won't do the absorption thing and the component then doesn't work as its supposed to. Metallurgy is a huge science all of its own, and then mixed with lubricants takes it to another level. Experience can show us to a degree what different oils etc can and can't do through trial and error, but for us laymen, that can be an expensive exercise,, The same applies for friction plates and rubbers used within a trans. If a cars a keeper, you want it to last for a long time.

Ultimately, everything wears, so to help with that, and to try and see if it can be kept at bay, changing oils frequently I think is a good idea. As said before, it can be expensive, but rebuilding engines, diff's and transmissions is a lot more expensive. Why manufacturers have gone down the extended path is purely financial, and the only gain in that, is for them, not us.

If you can afford it, having your oils tested like Shane does, I think is a great idea. He can tell from his results whats going with his car much better than most can, so it gives him the upper hand on whats going on and what may happen.
Having found numerous faults after dealers have had my cars, I trust no one. They all seem to take short cuts, or don't follow procedures correctly, or are just plain "to lazy" to do the job right. We do however have to have some faith in them, as we ourselves either don't have the time or maybe energy to do it ourselves. A sad fact of life.

Originally Posted by trout1105

Seriously, How hard can it be to undo the filler plug and dip the oil to have a look at it whilst the truck is up on the hoist especially with these extended service intervals???
It would maybe add another 5min to the service times which in all honesty are pretty well "Padded" and leave Plenty of time to do this.
It's Not all about what the service schedule dictates, It's more about just how good and thorough the workshop is when they service your vehicle Because as far as I am concerned fault finding and quickly checking out the rest of the vehicle should all be part of a service.

Dont shoot the messenger - if it is not in the service schedule a dealer will not do this unless asked.

At an Indy, most wont bother either BUT some might ask if you want them checked or at least discuss what additional work you would like in a service.

Thanks Shanegtr for your info from testing.

To the OP, I’ve had my d4 2011 for 4 or 5 months now and have just had my front diff replaced.

It was a decent whine from the front and similar metal contamination to yours. Near 200,000km, but bet fluids were never done! What a stupid idea when the qty is so small!!!

Anyway, I changed fluid three times and put in that nulon (g20?) additive which all did nothing.

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.

Originally Posted by andeck

Thanks Shanegtr for your info from testing.

To the OP, I’ve had my d4 2011 for 4 or 5 months now and have just had my front diff replaced.

It was a decent whine from the front and similar metal contamination to yours. Near 200,000km, but bet fluids were never done! What a stupid idea when the qty is so small!!!

Anyway, I changed fluid three times and put in that nulon (g20?) additive which all did nothing.

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.

G70 was the indicater.

Nulon G70 will reduce and sometimes eliminate gear whine.

But it will not reduce bearing noise