Trashed front differential

Hi all

I recently badly damaged the front differential of my 2012 model Jimny. Both front and rear diffs are equipped with Chinese air lockers - RD206 and RD208. The damage occurred when I was on a very steep and rough downhill and had to reverse because the road ahead got washed away by heavy rain. I had to air lock both diffs and use 4WD-4L to only just manage to reverse out. But just at the end of this, I heard a loud clink sound and the front diff became rather noisy. I think it happened because the rear diff leaks air (these O-rings wearing out so easily) and the locking mechanism dislodged when under heavy stress due to low air pressure.

I managed to return home and take the car to my mechanic, who found the front diff in a number of pieces in its enclosure. Mainly nuts, a bracket and a couple of other parts. His opinion (and mine) is that I need a new complete differential assembly, because the original is beyond repair. I had already ordered a new RD206 but the damage is general so now I am faced with the problem of finding a complete replacement front differential. As I live in a small country (Cyprus) such spares are not stocked by dealers and they would be much to dear in any case.

So I am looking for advice from the forum, how should I proceed? Try to find a new replacement? Try to find a pre-owned replacement? If so, could it be reliable enough to take the new RD206? Or should I water down my wine and avoid using air lockers, since they can break diffs? Could I find a reconditioned front diff from suppliers in Europe, if I have to?

My thanks in advance for any help.

Best regards

Neoklis

You will need a new 4.3 diff then (from 2005 on in VVT Jimnys).

I am a bit surprised that its the diff thats gone. I would expect a CV or halfshaft to go before that. What exactly has failed? You normally swap the crown wheel onto the air locker, so is it the chinese locker or the original diff parts that have gone? If its the locker, then I would be wary of buying another from the same place.

In the UK ARB air lockers are not much more money than the chinese ones, so thats what I have. Ive given them some abuse including snatch towing vehicles in reverse, never broken anything (yet!)

I have 2 sets of 4.3 diffs going spare (complete standard ones). I removed them from my cars when I went to 3.9 ratio and lockers. If they are the correct ratio for you I'm sure we could come to a deal. Not sure how much postage to Cyprus will cost tho!

Riccy wrote: You will need a new 4.3 diff then (from 2005 on in VVT Jimnys).

Hi Riccy, thanks for the reply. Not too sure about the type of diff it is (was), factory original 2012. I will find out, I have friends with formal mechanical engineering degrees and car enthusiasts, willing to help. My knowledge of car mechanics is limited.

Riccy wrote: I am a bit surprised that its the diff that,s gone. I would expect a CV or halfshaft to go before that. What exactly has failed? You normally swap the crown wheel onto the air locker, so is it the chinese locker or the original diff parts that have gone? If its the locker, then I would be wary of buying another from the same place.

I was also surprised that the diff was damaged. I was warned that using diff lockers could damage the locker, at least on hard surfaces or trying to steer. I was reversing on a very steep, rough and narrow downhill with a sharpish bend so I must have done all the wrong things, trying to get out of there. I believe the locker disengaged under heavy load, due to low air pressure, probably broke (its still in the crown wheel) and possibly parts of it fell in the diff itself and damaged it. Whatever the case, I think something would have broken even with ARB lockers, perhaps the parts you mention, under the circumstances.

Riccy wrote: I have 2 sets of 4.3 diffs going spare (complete standard ones). I removed them from my cars when I went to 3.9 ratio and lockers. If they are the correct ratio for you I'm sure we could come to a deal. Not sure how much postage to Cyprus will cost tho!

Likely it will cost a lot, but I will keep your offer in mind. I am considering other options too. Luckily for some reason, second hand cars have good prices here and I might trade it in for the new Jimny, much as I would hate to give it up, I made a lot of mods to it. But repairing the diff and installing the air locker will put me back to square one, and I will always hesitate to go to difficult places. The new Jimny 2019 seems to have its own factory slip limiting system which is much less likely to damage the car. Anyhow, with the front diff removed, my Jimny is still a lot better than a small saloon!

Have some images and vids of my Jimny on my website below.

Neok

www.5b4az.org/

To me this sounds like:

- Reversing
- upwards
- 4WD-L
- difflocker engaged
- steering to one side
- sufficient grip on bigger tires

This gives the highest forces and something must break.

Of course I would inspect the air locker an so on but it would be possible that everything is fine and there was no underlying problem - just too much force.

If you plan on doing this more often you would need a different axle (old Nissan or G) or car (Pinzgauer) and it could still be that you break something.

The durable solution for situations like this would be a rear winch.

RainerK wrote: To me this sounds like:

- Reversing
- upwards
- 4WD-L
- difflocker engaged
- steering to one side
- sufficient grip on bigger tires

This gives the highest forces and something must break.

Yes, you hit the nail square on the head! It was very muddy and slippery so I had no choice and even with all that above, I only just got out. I thought the slippery surface might give some way to transmission windup but I must have run over some rocks, that were also present.

RainerK wrote: Of course I would inspect the air locker an so on but it would be possible that everything is fine and there was no underlying problem - just too much force.

Yes, very likely it was too much force.

RainerK wrote: If you plan on doing this more often you would need a different axle (old Nissan or G) or car (Pinzgauer) and it could still be that you break something.

Well, I think better still, remember my age from time to time, 70+, and act accordingly! With my knees worn out, I think there is a lot less room for hard driving

Neoklis

Just out of curiosity what type and size of tyre are you using? It's just that I wouldn't expect even a cheap Chinese diff to fail using a modest tyre, maybe a 31 inch plus extreme mud tyre could ask too much of a diff but then something that big shouldn't need a locker to reverse out of a washout.