ARB Diff Locks, What is normal?

[ARB 4X4 Accessories Corporate Member Find all posts View Profile Close ARB 4X4 Accessories]

Hi CraigM, I've just shown your post to our head Air Locker engineer and whilst concurring with Crooza's comments about bearings, he's also offered another potential cause.

"A new diff does shed some of the surface carburisation from gears and thrust surfaces within the first 2500kms, and this is why the first service point is set at such a short interval (as per our service guide pg11). It's called a break-in interval.


For reference, the first service point for a new vehicle (or any petrol motor driven equipment) is also very short for the same reason - so all the fluids can be changed out to flush the particulate from the break-in process.


If the initial service was missed and the diff hasn't been touched in 12 months (usually considered to be 20,000kms per year) then you might have created milky oil by literally grinding up all of the break-in particulate for far too long. Given you haven't found any large particles, indicative of heavy wear or damage, I would suggest driving it for another 5000k's on the fresh oil and then have another look at it for particulate."

He also suggested that over preloading bearings in the rear of a 120 V6 Prado is not a common issue, although shouldn't be discounted as a possible cause.

Hope this helps.

Cheers, Sam.

[craigm Addicted PP Member Find all posts View Profile Close craigm]

Thanks Sam, really appreciate you taking time to respond. I can't recall reading page 11 of the service guide (probably in the bottom of the Air Locker box with my left over diff centre). I dont recall the dealer mentioning to me either that I should bring the vehicle back for a diff oil change and inspection, or get someone else to. The only thing he mentioned was to ensure that the diff is engaged at least monthly.The Prado has probably traveled 15000k's since the install on the same oil, so may well be a contributing factor as you have suggested. I will await my dealers report to see what is found.
I

[ARB 4X4 Accessories Corporate Member Find all posts View Profile Close ARB 4X4 Accessories]

Thanks Sam, really appreciate you taking time to respond. I can't recall reading page 11 of the service guide (probably in the bottom of the Air Locker box with my left over diff centre). I dont recall the dealer mentioning to me either that I should bring the vehicle back for a diff oil change and inspection, or get someone else to. The only thing he mentioned was to ensure that the diff is engaged at least monthly.The Prado has probably traveled 15000k's since the install on the same oil, so may well be a contributing factor as you have suggested. I will await my dealers report to see what is found.
I

No probs at all. Happy to provide some further advice if needed.

Let me know how you go.

Cheers, Sam.

[craigm Addicted PP Member Find all posts View Profile Close craigm]

OK, dropped the Prado into the store where my rear Air Locker was fitted just on 12 mths ago. Apart from what looks to be a blown seal causing an abnormal amount of Diff oil exiting the compressor, my mechanic reported very metallic diff oil when he dropped the oil for it's 160K service.
Now the store's mechanic and owner, told me that this is normal for a diff with a locker? Is this correct? Pics below of the state of the oil. There were no metal shavings or particles, just this shiny silver goopy oil. I would expect diff oil to get dirty, but not silver! Wouldnt having a locker help the oil last longer and stay cleaner than one with an LSD?

Hi CraigM, I've just shown your post to our head Air Locker engineer and whilst concurring with Crooza's comments about bearings, he's also offered another potential cause.

"A new diff does shed some of the surface carburisation from gears and thrust surfaces within the first 2500kms, and this is why the first service point is set at such a short interval (as per our service guide pg11). It's called a break-in interval.


For reference, the first service point for a new vehicle (or any petrol motor driven equipment) is also very short for the same reason - so all the fluids can be changed out to flush the particulate from the break-in process.


If the initial service was missed and the diff hasn't been touched in 12 months (usually considered to be 20,000kms per year) then you might have created milky oil by literally grinding up all of the break-in particulate for far too long. Given you haven't found any large particles, indicative of heavy wear or damage, I would suggest driving it for another 5000k's on the fresh oil and then have another look at it for particulate."

He also suggested that over preloading bearings in the rear of a 120 V6 Prado is not a common issue, although shouldn't be discounted as a possible cause.

Hope this helps.

Cheers, Sam.

Ok... So I have just had my 170K service which also included a pre-cape trip check which was pretty thorough. My mechanic dipped his finger in the diff oil to check it's state as he was serviced my Prado at 160K and alerted me to the oil condition last time. To his (and mine) surprise, he found the oil not clear and golden as one would expect from a diff that had only done 10K since the last diff oil change. My mechanic replaced the oi at 159600K and then the Prado was taken back to the ARB dealer and attended to where they again dropped the oil, serviced the diff and changed the oil (this time with a greeny coloured oil which is different to what my mech supplied. The oil is "Very" dirty and you can see some metalilc particles (partculate as ARB call it) in it as you can see in the image



So I think this time I will take it to ARB Nundah (Qld state office) to see what they think. I wasn't fully convinced on the dealers response last time (metal in the oil is normal after a locker install and I should have changed the oil after 5K - Bahhh!!!)
Welcome to hear anyones opinion who is more knowledgeable than I on this one... (which wouldn't be hard) and invite our friendly ARB rep to discuss again with their air locker engineer...

[ARB 4X4 Accessories Corporate Member Find all posts View Profile Close ARB 4X4 Accessories]

Hey craigm, I flagged your recent comments with Daniel, our chief Air Locker extraordinaire. He's provided the following.

Firstly, the 10,000 km oil in this picture looks actually pretty clean for 10,000km oil.

Somebody recommended 'Castrol 90'. Most in this thread are from Queensland, and if you are really 'using' your vehicle then 90 is just not the right viscosity (too thin). Castrol make some good oils - everybody knows that - and they also make some bottom shelf economic options to sell out of petrol stations - so quoting 'Castrol 90' without an actual grade doesn't exclude the possibility of running sub-standard oil for the application.

It's worth noting that Prado's are known for flexing around in the rear, especially if they are loaded up a bit. As soon as you have any flex in the diff third member you lose optimal ring and pinion mesh, and start wearing very very fine particles, the kind that results in gloppy oil rather than actual chips of metal, and that's more like what we see here. If you have ever had a drive pinion changed then there could be an issue with the running mark. Otherwise, a good oil might sort this out.

Another note I had was the mention that the oil in both front and rear diffs looked the same. That likely rules out mechanical failure or set-up, as it would be rare to see it identically in both ends. So for me this would be another vote to either inferior oil grade or water contamination.

[Photo with your finger in the oil] I wasn't too convinced that this picture didn't look like evidence of possible water contamination. It may be worthwhile extending your diff breathers, if you haven't already.


Hopefully this is of some use to you.

Cheers
Dave

[craigm Addicted PP Member Find all posts View Profile Close craigm]

Thanks for your response Dave. re the latest 10000km oil change. the image shown is a very thin smear in a white plastic bowl. what is seen in a clear jar is very dark and dirty. I dont understand how a diff can have it's oil so dirty after just 10000km of mild use. (locker used probably a dozen times in the last few months and engaged monthly as suggested by the store manager. My mechanic mentioned to me that the silvery oil in the first sample was definately not water contamination and as I have had diff breathers extended well before my locker was installed, rules out this possibility. I will take the oil into a local Diff specialist and get his opinion before I again approach the ARB store manager. I just dont want to find that the diff has abnormal wear and tear due to improper installation/setup and that the ARB warranty has expired and left with a hefty repair bill. I am heading up the Cape in 3 weeks and would like peace of mind before I leave....

[AussieAndy Find all posts View Profile Close AussieAndy]

Hey Craig, hit up diff lapping at kedron. They are the business when it comes to diffs, if they don't know it, it's not worth knowing kinda thing. I would get their opinion on it and go from there.

Cheers,
Andy

[craigm Addicted PP Member Find all posts View Profile Close craigm]

Haha!! Great minds Andy... I gave them a call earlier today and told him the story. What a great bloke! More than helpful. I asked him if i bought the last dump of diff oil down to him would he have a look and let me know if there is any cause for concern. Not a problem. I'll drop in to their workshop next week for his thoughts.

Cheers


Sent from my iPhone using Tapatalk

[AussieAndy Find all posts View Profile Close AussieAndy]

How did you go Craig, what did the gents at diff lapping have to say??