Front Locker for NJ Auto

Joined: 10 Jun 2008 Location: Logan

Hi all, If been searching the forums for an answer to this but can't find one, so hoping someone might be able to help me.
I have a '94 NJ 3.0L Auto and I want a front locker for it.
Apparently their not available for the auto, so what I'd like to know is can I swap the front diff for one out of a manual.
Does anyone know what the difference is?
Also my Gregory's workshop manual says the rear diff is either a locker or LSD, But guess what, it isn't either. I don't understand why anyone would fit an open diff to a 4x4.
Thanks in advance guys.
Gary

Joined: 11 Jan 2004 Location: Adelaide

Not sure precisely what the differences are (search here long enough and it's all been discussed) but I think it's essentially 7.5" (auto) vs 8" (manual.) I believe it is possible to swap them over, but not sure what's involved. Just make sure you get the right ratio.

How do you know you don't have an LSD? I thought I was without one for a year or two, until I learned how they really work - and discovered mine works well. armsup

Even a good LSD will slip under the wrong circumstances. A few clicks on the handbrake normally makes all the difference. Wink

Joined: 18 Nov 2004 Location: New Zealand

Yes the 8 inch diff bolts straight in. To do the swap you also need the 8 inch drive shaft as the pinion is longer and so driveshaft shorter.

Otherwise thats all you need.

Joined: 10 Jun 2008 Location: Logan

Oh goodo, I'll start looking for one. I just noticed the front seal is leaking.
As for the rear, I was told the only way to tell if you have an LSD is jack up one wheel and try and drive off the jack. So I did, the raised wheel just spun.
So based on that I don't have an LSD.
Thanks for your help fellas
PS. I'll tell the missus it's cheaper to replace the diff than the seal. That should get me one Wink

Joined: 18 Nov 2004 Location: New Zealand

NO trying to drive off the jack is not how a LSD works. You would need a locker or a highly modified (more shims) LSD to drive off a jack.

So that test doesn't and won't work.

What would work better is doing a burnout on tarseal.... Very Happy

But seriously jack up both back wheels and rotate one. Leave the vehicle in gear. If the wheel opposite the one you spin turns the same way then you have an LSD. If its the opposite then open.

Typically this method will work.

As Scott eluded to, they require some sort of resistance to work propeerly so when you are cross axles a LSD won't get you out. But if proir to getting crossaxled you have the handbrake on a few clicks so it is just dragging then it can be very effective.

I don't have one anymore but I think that's what Scott was referring too... Wink

Joined: 10 Jun 2008 Location: Logan

Ok, I'll give that a go.
Thanks Mate

Joined: 11 Jan 2004 Location: Adelaide

NJV6 wrote:

But seriously jack up both back wheels and rotate one. Leave the vehicle in gear. If the wheel opposite the one you spin turns the same way then you have an LSD. If its the opposite then open.

Typically this method will work.

Um, no. If the vehicle is left in gear the prop-shaft can't turn, so the diff has no choice but to spin the opposite wheel in the opposite direction - LSD or not.

The prop-shaft must be free to turn. With an open diff, it's easier for the axle you are turning to turn the side gears (and spin the other axle in the opposite direction) than turn the crownwheel, pinion and prop-shaft.

With an LSD, to spin the side gears requires the clutch packs to slip. It's easier for the axle to turn the crownwheel, pinion and prop-shaft than it is to slip the clutch packs. If the prop-shaft cannot turn (i.e. in gear) then the only way to turn one wheel is to slip the clutch packs and cause the other wheel to turn.

This is Mitsubishi's official test for the clutch packs. Special adaptor on the hub, and measure the torque required to turn the wheel (and force the LSD to slip.) If it requires enough torque the packs are considered to be OK (or your bearings are completely shagged. Wink

)

NJV6 wrote:

As Scott eluded to, they require some sort of resistance to work propeerly so when you are cross axles a LSD won't get you out. But if proir to getting crossaxled you have the handbrake on a few clicks so it is just dragging then it can be very effective.

I don't have one anymore but I think that's what Scott was referring too... Wink

I think so too. Laughing

Mitsubishi LSDs (well, the earlier ones) are "ramp loading" (like Nissan LSDs) - they tighten as more load is applied. When one wheel is off the ground, there is little resistance and the packs slip easily. Add some resistance (such as the handbrake), increase the load on the packs and they grip better - the slip is limited. Wink

It's got me out of trouble a couple of times.

Joined: 18 Nov 2004 Location: New Zealand

-Scott- wrote:

Um, no.

I knew that! Just checking you did too... Embarassed

Joined: 11 Jan 2004 Location: Adelaide

NJV6 wrote:

-Scott- wrote:

Um, no.

I knew that! Just checking you did too... Embarassed

So, did I pass the test? Very Happy

Joined: 10 Jun 2008 Location: Logan

So how do I check if the diff is open or LSD?

Joined: 18 Jan 2003 Location: melb

More than likely would have one if it's a GLS as most of them did, but you can check for a bright orange sticker in the drivers side door opening.
Dave

Joined: 18 Nov 2004 Location: New Zealand

barneymutt wrote:

So how do I check if the diff is open or LSD?

Read above posts.....

Joined: 10 Jun 2008 Location: Logan

The above post's don't make any sense to me.
I've never had any experience with an LSD.
I haven't noticed a bright orange sticker but will have a look.

Joined: 10 Jun 2008 Location: Logan

Well bugger me, I've never noticed that bright orange sticker before.
Thanks Mr Pickle Embarassed

Thank you also NJV6 and Scott.

Joined: 18 Nov 2004 Location: New Zealand

barneymutt wrote:

The above post's don't make any sense to me.

NJV6 wrote:

But seriously jack up both back wheels and rotate one. Make sure the vehicle is in Neutral. If the wheel opposite the one you spin turns the same way then you have an LSD. If its the opposite then open.

I just corrected the piece I got wrong which Scott corrected me in the later post.

Joined: 10 Jun 2008 Location: Logan

Hi guys,
I went and saw a chap at ARB Coopers Plains and he couldn't have been more helpful. He told me the reason ARB don't do a front locker for an auto is the diff internals are just too small to fit in the locker. So in order to get one I'll have to swap it for a manual diff.
I thought I'd share this in case others wondered the same thing.

Joined: 18 Nov 2004 Location: New Zealand

Good to see you read the 1st two responses to your original post........ #Sleep

Joined: 14 Apr 2005 Location: Geelong VIC

NJV6 wrote:

Good to see you read the 1st two responses to your original post........ #Sleep

I think hes refering to WHY no one makes a front locker, which there is no answer to in the reply posts.

Joined: 27 Dec 2004 Location: Maffra Victoria

hey Scott - This resistance thing and LSD's you mentioned that the back wheels need a bit of resistance and thats where the handbrake comes in................. Razz

Trust me I've tried (in vain) to get my handbrake to wedge herself under a spinning rear wheel - but never been successful Exclamation

. Though I've found getting your handbrake to push can work wonders sometimes...........LOL

Lambie Very Happy