Broken factory Locker

[NJV6]

I broke my locker today. :( It is a 4.900 ratio one and so its a bit rare and wondering where to start and why it broke.

Well I kind of know why - the right foot was giving it a little more treatment than I'd like and I had 2 sets of chains on 33's and trying to climb a 30m bank at 30 degrees where only a bulldozer had ever been down many years ago. All well and good but the bank was uneven and bedrock.... = very hard on gear. I winched a bit then disconnected, gave it the jandle then BANG.

I still works perfectly as an open diff, it is not noisy or anything untoward but the locker doesn't work. The compressor runs, dash light flashes then goes solid as if it's in but no, its not.

I have not had one apart before and was hoping for some suggestions.

cheers, Glen

[Overkill]

I broke my locker today.

BUGGER!

[Ian Sharpe]

Bugger man,


you'll have to pull out the diff centre & suss outs whats going on.

[Ian Sharpe]

Could be a broken axle, if it is you'd better hope its the drivers side, as the other side is shorter & therefore as rare as the locker itself.

I have never heard of anything in the 12 bolt diff breaking, but hey there always has to be a first.!!

PS , did you swap in the locker or was it on the car when you got it. If its factory optioned then yours is indeed a rare beast.

How do you find the 4.90 diffs. I did not find them anything exciting when I swapped them into my previous NK 3.5l.

cheers

[J Top]

Hi NJ
I have 2 x 3 litre ones here. They don't like driving home with a broken axle!!
To prevent this happening do a SAS, or at least fit a front locker, so that the front does some work as well.
Drain the oil and see what comes out.
I wonder if they jump out of mesh and maybe need some more air pressure to keep them in like the Patrols do.
If I can help let me know
J Top

[NJV6]

HI guys,

Yea bugger and it is not a broken axle as it still works fine as an open diff, I had done this axle swap myself Ian about 2 months ago & did the writeup on here about it. I find the 4.9's better on the road if nothing else with 33's it brings by revs up a little for cruising.

Now JTop I suspect you could be right about the pressure thing. There has been a number of times when I have had the locker in and the light on the dash has given the odd flicker as if to say 'im not fully in'. I wonder if this has been the case and when under severe pain, not fully engaged it has done its thing.

And yes a SAS or diff lock is an option and with this episode I have decided on some lower gears too.....

[Ian Sharpe]

well it could be that one or some of the locking teeth have broken off & are preventing the mechanism from locking.

You wont know until you pull the diff centre out.

I had 2 locking teeth break off, but it still works.

I priced a new hemishere, it was over $2k!!!

Bugger that for a joke.

If ARB come through with the 3.5 rear locker, I'll convert to that.

cheers

[NJV6]

2K! please don't tell me that! After all the trouble I went to to get the bloody thing!!
http://www.outerlimits4x4.com/PHP_Modul ... hp?t=71431

How did you know you broke 2 teeth off, other than looking - i mean what made you go looking?

[Ian Sharpe]

Accidently engaged locker whilst going round corner, only slow though but it was still enough to give loud shudder & break teeth. Wouldnt lock anymore so took the diff centre out. One tooth had fallen in the soup & was caught on the magnet.

The other was still hanging on preventing the diff from locking properly, busted it off & refitted. Still works Ok, there are many teeth so missing a couple wont effect it too much IMO, but I wouldnt want to loose more than a couple.

While the 3.5 diff is pretty tough, IMO the locking mechanism is the weakest link, each tooth is only about 1/4" x 1/4 " & can easily bust off.

Unfortunaltely the locking teeth are part of the hemisphere.

ARB seem to have a better locking mechanism.

cheers

[NJV6]

Right - so I'm going to pull it out asap and have a look to see what the damage is. Yes, I agree the ARB's are better and they almost always go in immediately, which may have been the demise of mine, not being fully in - Im not sure.

Without looking inside, will an arb centre fit into an existing locker - or will I need to change back to my 4.636's? I've gone to the 4.9 effort of changing the front and back over.
Actually thinking about it, I should be able to keep my 4.9 crown wheel and pinion?

Glen

[Ian Sharpe]

Glen,

ARB dont do a locker for the 12 bolt diff, though one is apparantly in the pipeline. ARB do a locker for the smaller 10 bolt diff found in the 3.ol but that cant be fitted to the 3.5 diff. Different size , different axle splines etc. There was a post here from Daniel from ARB outlining what modifications would be needed to use the ARB 10 bolt diff in the 3.5l housing, there were some serious mods I think. Here is the link.

http://www.outerlimits4x4.com/PHP_Modul ... hp?t=51521
If the problem is indeed broken locking teeth, it really depends upon the extent of the damage as to whether its still useable or not. As I said i reckon a couple of teeth dont seem to make any difference, but it could turn out to be a different problem all together.!

If the diff is beyond repair , here are your options I reckon.

1. Refit original diff & swap over your 4.90 c/w, its a straight swap & that way you dont have to worry about re swapping the front. Take it tio a diff place & have it set up properly though. You dont need to change the housing, just the diff centre & original left side axle. This option means no locker.

2. Do 1 as above & wait (hope) that ARB come thru with the 3.5l locker.

3. Source a complete rear end from a 3.ol paj, make sure its a 4.875 ratio, that way it will be only .5% different from your 4.90. Fit an ARB locker to that, you get beefed up hemishpere etc & strong ARB locking mechanism. You will of course loose the stronger 31 spline axles that come with the 3.5l diff. Also the 3.ol diff housing had a tendency to crack, but you could have it braced before fitting.

I was going to do this with mine before I managed to source an original locker.

4. Try to find another original 3.5 locker but as you & I know they are as rare as.

5. Bite the bullet & get new parts from Mitsu.


I would do 1 above & wait for the ARB, last report was that it could be out by end of year, however who knows, the RD110 was delayed quite a few times before it eventually got released & then recalled before any were fitted.

Good luck & let us all know the outcome when you pull it down.

[NJV6]

If the problem is indeed broken locking teeth, it really depends upon the extent of the damage as to whether its still useable or not.

Yes, time for a strip.

1. Refit original diff & swap over your 4.90 c/w, its a straight swap & that way you dont have to worry about re swapping the front. Take it tio a diff place & have it set up properly though. You dont need to change the housing, just the diff centre & original left side axle. This option means no locker.

I like that idea if it's poked. My 4.636 had a LSD in it anyway.

2. Do 1 as above & wait (hope) that ARB come thru with the 3.5l locker.

yep

3. Source a complete rear end from a 3.ol paj, make sure its a 4.875 ratio, that way it will be only .5% different from your 4.90. Fit an ARB locker to that, you get beefed up hemishpere etc & strong ARB locking mechanism. You will of course loose the stronger 31 spline axles that come with the 3.5l diff. Also the 3.ol diff housing had a tendency to crack, but you could have it braced before fitting.

I was going to do this with mine before I managed to source an original locker.

Tis another option, however I'm not sure about doing all that + a locker on a slightly weaker setup than I had. I'd prob prefer to wait patiently for a 3.5 locker, however after having one for a few months its wicked. I have seen locker assembly's (3.0) here on Trade me for around $700

4. Try to find another original 3.5 locker but as you & I know they are as rare as.

Ha ha - yea right

5. Bite the bullet & get new parts from Mitsu.

well I can only price it - they don't charge for asking - yet

Good luck & let us all know the outcome when you pull it down.

sure will. thanks for your efforts here Ian. I went into the Mitsi dealer today and pretty much got blank faces when it came to the diff lock - seems I knew more than them and I haven't even had one apart! one helppful chap got out the service manual but it didn't ahve an exploded diagram or anything in it.


cheers, Glen

[Ian Sharpe]

but it didn't ahve an exploded diagram or anything in it.


cheers, Glen

Glen,

Unfortunately the exploded parts view doesnt really show the locking teeth in any detail, except to indicate its all part of the hemisphere. I checked this out before.

Yes I agree about the value of the rear locker, BUT I seriously reckon that the front locker RD110 makes a better improvement for the Paj, believe me I have both.

Thats another option for you, just get your old lsd back & get the front locker from ARB.

cheers

[Bitsamissin]

If it was me and the locker was trashed I'd be putting the lsd centre back in with the 4.90 C&P and investing in RD110.
The car will be more capable offroad than with just the rear locker and open front.
Then I'd be waiting for the 3.5 ARB rear locker the end of the year seems like a long time but it will be here before we know it.
I was told that the gear locking mechanism is the weak spot in the Mitsu locker and being a low pressure design (6-psi) engagement/disengagement isn't instantaneous at times and it's easier to break teeth off if it is half locked under load.
Thats what I like about the ARB being high pressure the locking mechanism moves immediately.

[cookie monster]

if the teeth have broken off the locking ring, why not take the locking ring to a toolroom and have them make you a new one. now i havent seen any pics of one but im sure someone could cnc machine you one. not sure what they would charge though. australian going rate would be $65 to $85 per hour. i would guess it would be a $600 job(very big guess!)
cookie monster

[NJV6]

ARGH!! All this talk about the front locker and I don't know what to do - I keep thinking SAS and don't want to invest in the RD110 only to discard it in 12 months time!

But it might be as good a thing as I need, to get a front locker with my Infinitely Fantastic Suspension....

We are talking about the rear here guys - REAR! I have enough trouble telling myself I don't need a SA on the front!!!

I feel you might be right Frank about the low pressure. I have a suspicion it wasn't really fully locked up and it was under severe load.

[Overkill]

ARGH!! All this talk about the front locker and I don't know what to do - I keep thinking SAS and don't want to invest in the RD110 only to discard it in 12 months time!

I'll buy it off you in a years time when you do your SAS! Don't go hard enough to warrant a SAS but could do with a front locker.

[klrevo]

or i will....

dean

[Ian Sharpe]

if the teeth have broken off the locking ring, why not take the locking ring to a toolroom and have them make you a new one. now i havent seen any pics of one but im sure someone could cnc machine you one. not sure what they would charge though. australian going rate would be $65 to $85 per hour. i would guess it would be a $600 job(very big guess!)
cookie monster

The unit that has the locking teeth cut into it is welded to the hemishpere, thus it forms part of the hemisphere & is not serviceable.

Glenn,

Frank is right here , the front locker is THAT good!. Unless you do absolute hard core stuff then I reckon you'd be happy with the IFS & front locker. I dont know how much you were going to spend on a live front end but surely the RD110 would be cheaper!

Then fit the ARB rear when it comes on the market.

cheers

[NJV6]

I think this picture explains itself......



Glen

[Ian Sharpe]

Faaarrk

No wonder it dont work, its broke!.

Thats bad luck mate.

Hurray up ARB with that rear locker!!

[NJV6]

here here. Hurry up indeed. It seems to replace the unit will be as much as an arb unit & still possibly not as strong.

If I have done it once, what is to stop it doing it again? I am sure I was not as hard on things as some people, I have never bent an idler arm or damaged a CV, must have been one of those things.

I am also quite certain that the locker cannot have been fully engaged. With the diff out and still connected to the air line and operating it, everything seems to move properly however.

The worst thing about it all is, I went to such lengths to get the jolly thing, got the compressor etc.
Someone hurry up and break a short side axle on a 3.5...!!!!! For I have one i'll swap for an ARB unit when it comes out...

[Ian Sharpe]

Yeah mate I can feel for ya!.

Took me 18 months to track one day her in Oz.

BTW when you installed it , did you hook up the switch in the diff, so that it displays the dash icon??


I did this with mine & it tells you definately when the diff is locked or not. As you know it doesnt always engage/disengae straight away.

In fact when I installed my ARB front , I asked greg Milton (from ARB) why they dont have a sensor in the diff so that you can illuminate a light to let you know if the diff is locked or not.

His reply was that because ARB use 100psi as opposed to 6psi (with Mits) they dont really need a sensor because the diff engages straight away because of the high presssure.

But I still reckon a sensor would be good because you just never never know IMO.

Out of interest I will ask my local Mitsu dealer what the cost of a hemisphere is. Some Mitsu stuff like that has come down in price over the past couple of years, I dont know why though.

I'll post the results of my enquiry.

cheers

[Ian Sharpe]

Glen,

I called into my local dealer yesterday.

the hemisphere is part num MR 165540

cost $2029 retail!!!!!!!

guess you'll be waiting for the ARB??

cheers

[Alex Kogan]

You could try lookup accross the pond. Here stateside locker was standard equipment on all Mitsu Montero(same as Pajero) SR(not LS) 94 through 97 then later all Models (there was only one) 98-99. You can get rear carrier as cheap as US $150 as long as they would be willing to ship it. Still going to be much cheaper. Ideally you'd need to take hemisphier out, but usually they will only sell 3rd member. Also you are pretty much gurantied that it never saw any action.
Here is a good site to look up used parts (look for carrier(differential). http://car-part.com/ it asks for ZIP you can use 64155 for example.

[NJV6]

Hi Alex, so what is a SR as opposed to a LS?

What ideally I'd need is a 4.9 ratio centre for the 35.5mm rear axle.

Cheer,s Glen

[Alex Kogan]

SR is equivalent of GLS I guess - top of the line truck with all bells and whistles: 3.5L, leather, locker, bigger axle, sunroof so on. LS had smaller 3.0L, cloth, open diff, etc. Unfortunately there is no 4.9 since it was installed on 2.8TD and we never saw this one. You’ll either get 4.636, or 4.272. But you could always swap you gear on. Shipping hemisphere ~30lb would be quite a bit cheaper then 100lb 3rd member (center) also.
Btt. if you going to look for one check 95-99, 94 model was swapped mid year and it might have been optional.

[Alex Kogan]

Yeah mate I can feel for ya!.

Took me 18 months to track one day her in Oz.

BTW when you installed it , did you hook up the switch in the diff, so that it displays the dash icon??


I did this with mine & it tells you definately when the diff is locked or not. As you know it doesnt always engage/disengae straight away.

In fact when I installed my ARB front , I asked greg Milton (from ARB) why they dont have a sensor in the diff so that you can illuminate a light to let you know if the diff is locked or not.

His reply was that because ARB use 100psi as opposed to 6psi (with Mits) they dont really need a sensor because the diff engages straight away because of the high presssure.

But I still reckon a sensor would be good because you just never never know IMO.

Out of interest I will ask my local Mitsu dealer what the cost of a hemisphere is. Some Mitsu stuff like that has come down in price over the past couple of years, I dont know why though.

I'll post the results of my enquiry.

cheers

I'd say such sensor would have added quite a bit to price of the locker. Most of people would prefer to save those for something else.

You can get new hemispher for a bit less stateside but still it's about AU$1500