Outer Limits 4x4 Board

The next project in line for my 1999 s2 disco is locking diffs. I am considering either ARB air lockers front and back or a land rover mechanic has quoted me for fitting a centre diff lock. My question is, will this interfere with the existing traction control system in anyway and when locks are not enganged, will the traction control work as normal. Any advice / suggestions are very much appreciated. Also has anyone done anything similar and has any advice.
Aye

your on the gold coast..... if you want to spend $$$ get in touch with Mal @ Maxi Drive (in carrara).

Mick G wrote:The next project in line for my 1999 s2 disco is locking diffs. I am considering either ARB air lockers front and back or a land rover mechanic has quoted me for fitting a centre diff lock. My question is, will this interfere with the existing traction control system in anyway and when locks are not enganged, will the traction control work as normal. Any advice / suggestions are very much appreciated. Also has anyone done anything similar and has any advice.
Aye

Once diff lock is activated t/control wont function as all wheels are locked,
t/control reqires different wheel speed to function.

Michael.

Thanks Michael

I didn't word my question that well. If I do fit locking diffs, when these are disengaged, will the standard traction control then work as normal, say on the drive home, or by me fitting locking diffs am I saying goodbye to the factory traction control for good? Plus, by fitting locking diffs, will I be damaging the traction control system when using the locked diffs?

Aye again

I would do the centre difflock first. If you start the car while the centre difflock is engaged, it will switch off the traction control. The way it knows the diff lock is engaged is via the difflock light. Therefore if you want the traction control to stay on, you need to put in a switch to disconnect the light while you start the car or start the car withut the centre difflock engaged and engage it once the motor is running. Running a rear difflock will still allow the traction control to work in the front. But if you have front, rear, and centre difflocks engaged, traction control is not required.

Hello mate,

You talk about havin a center diff lock fitted?
Are you not aware that the diff lock is already present but not connected?
All disco 11 hav center diff lock but no fitted linkage.
Also the traction control does not give a shit if the center diff locks engaged or not.

I sincerely hope this saves you some money!

IIRC, the 99 Disco had the centre difflock, but just not the ability to lock it in via the in-cab shifter. It's not all that expensive (a few hundred $$$) to get a switch installed to do this. This will give a moderate improvement in off-road ability but good value for the money and definately necessary if you will use it offroad a bit.

Cross-axle difflocks will give a huge increase in offroad ability but also cost a lot more. ARB's are fine if you aren't doing anything to serious but i would be concerned about the std axles in the long run. Other options include McNamara and MaxiDrive. These both come with upgraded axles. You could still get ARB's and upgrade the axles seperately though.

Sorry forgot to say that if using locking diffs as far as i am aware the traction control has no adverse affects and proper use is quite unhindered.
Even with big tyres like simex.

As you c an see I am pretty new to thw whole 4x4 tech side, I'm learning quick though!! I'm leaning towards the centre diff lock as I was aware that it was fitted but just no way of locking from the cab. Am I right in saying a centre diff lock will do the same as front and rear lockers. I thought a centre diff will lock all wheels so they turn at the same speed, so in theory, only one wheel needs to be in contact with the ground.
Again everyone's wealth of knowledge is much appreciated.

Aye

Mick G wrote:As you c an see I am pretty new to thw whole 4x4 tech side, I'm learning quick though!! I'm leaning towards the centre diff lock as I was aware that it was fitted but just no way of locking from the cab. Am I right in saying a centre diff lock will do the same as front and rear lockers. I thought a centre diff will lock all wheels so they turn at the same speed, so in theory, only one wheel needs to be in contact with the ground.
Again everyone's wealth of knowledge is much appreciated.

Aye

NO,
centre diff lock only locks front to rear, IE: both front and rear drive shafts.

Michael.

Excuse my ignorance but what does that mean in actual driving terms, i.e. what is each wheel doing?

Aye

Mick G wrote:Excuse my ignorance but what does that mean in actual driving terms, i.e. what is each wheel doing?

Aye

this means that one fron wheel and one rear wheel are driving the car whille the centre is locked. IE : one wheel on each axle can spin when it looses trcation.

Michael.

You will have one front and one rear wheel providing drive when the centre diff is locked, when unlocked you will just have drive to one of the four wheels. If you want to have drive to both rears or both fronts, you require a cross axle diff lock.

Luke

Edit: Beaten Gotta refresh more often

What Micheal is trying to say is, God this could get complicated!

Basicly imagine your vehicle as one wheel drive....
If you jack one wheel of the ground and place the vehicle in gear, the wheel of the ground will spin and you will stay on the jack.
However......
If you engage the center difflock and then try to drive, you will drive of the jack as you now have drive to front and rear axles.
The other way of putting this is " the drive will go to the wheel of least resistance"
So basiclly your truck has one wheel drive and a fair traction control system.
Are you getting where i'm comin from?
Connect the center difflock, things that go 'clonk' work. Why Landrover discontinued the linkage we'll never know.

Best of luck Bud.

Mick G wrote:Excuse my ignorance but what does that mean in actual driving terms, i.e. what is each wheel doing?

Aye

With all diffs unlocked (centre, front and rear) in high traction situations power will go to all four wheels BUT in low traction situations power may only go to one wheel. It will be transmitted to the wheel with the least resistance ie wheel in the air, so as you can imagine this is bad as the wheels with traction ie on the ground are getting no power.

Now, if you lock the centre diff lock, you will have maximum of four wheels getting power and a minimum of two (one front and one back) in low traction situations.

Add a rear difflock and you will have a minimum of three wheels with power (both rear and one front, assuming centre difflock is engaged).

Add front difflock and all four wheels will have equal amounts of power being distributed. So in this situation you could have three wheels in the air and still have power to the wheel on the ground.

Clear as mud???

Bloody hell it is complicated, you dont know if you dont ask though!! Appreciate everyone's input.......it must be like going back to school for you all with novices like me!! I think connecting up my centre diff is first on the agenda (why did LR disconect it in the first place we'll never know.....or maybe someone does?) I like the idea of front and rear lockers though! Maybe fit these down the track once I have bounced the disco around a bit and got myself stuck good and proper.......wouldn't have it any other way!!

Cheers guys

Bloody hell it is complicated, you dont know if you dont ask though!! Appreciate everyone's input.......it must be like going back to school for you all with novices like me!! I think connecting up my centre diff is first on the agenda (why did LR disconect it in the first place we'll never know.....or maybe someone does?) I like the idea of front and rear lockers though! Maybe fit these down the track once I have bounced the disco around a bit and got myself stuck good and proper.......wouldn't have it any other way!!

Cheers guys

LR apparently got rid of the centre difflock because they thought their traction control was the bees knees. In the real world however it has a lot of shortcomings. Offroad ability is less important to LR these days anyway, who needs a centre difflock to take the kids to the footy?

Getting the centre difflock first is a good idea. You'll be suprised how far you can go with it locked in. The TC will also assist in this regard (its worthwhile hooking the TC up to a switch though - it can be dangerous in some situations).

Another good idea is join a club, and get out there and learn.

BTW, welcome Newbie!!!

Why did LR disconnect the centre diff???

Some boffin in the UK decided ETC was the way to go and that centre d/lock would never be needed, biggest mistake they ever made.

Michael.

HSV Rangie wrote:Why did LR disconnect the centre diff???

Some boffin in the UK decided ETC was the way to go and that centre d/lock would never be needed, biggest mistake they ever made.

Michael.

Here here

TuffRR wrote:LR apparently got rid of the centre difflock because they thought their traction control was the bees knees. In the real world however it has a lot of shortcomings. Offroad ability is less important to LR these days anyway, who needs a centre difflock to take the kids to the footy?

Getting the centre difflock first is a good idea. You'll be suprised how far you can go with it locked in. The TC will also assist in this regard (its worthwhile hooking the TC up to a switch though - it can be dangerous in some situations).

Another good idea is join a club, and get out there and learn.

BTW, welcome Newbie!!!

By hooking the TC to a switch, do you mean I will be able to switch it on and off from the cab and choose between the diff lock or TC? Am looking into joining a club as well. Any suggestions on the Gold Coast?

Aye

Mick G wrote:By hooking the TC to a switch, do you mean I will be able to switch it on and off from the cab and choose between the diff lock or TC?
Aye

Yep, thats pretty much it. Although its not really a matter of choosing between the two, I'd always use the CDL and TC in low traction situations and just use the switch to turn the TC off in situations when you don't want it working ie sand and reversing down slippery hills.

TuffRR wrote:

Mick G wrote:By hooking the TC to a switch, do you mean I will be able to switch it on and off from the cab and choose between the diff lock or TC?
Aye

Yep, thats pretty much it. Although its not really a matter of choosing between the two, I'd always use the CDL and TC in low traction situations and just use the switch to turn the TC off in situations when you don't want it working ie sand and reversing down slippery hills.

Sounds good to me, know anywhere on the Gold Coast where I can get something like that fitted for reasonable $$.

Aye

Mick, the traction control will switch off if you start it with the centre difflock engaged, so make sure you put a switch in to disconnect the diff lock sensor when starting. Just using traction control when reversing down a hill can cause the front wheels to lock up and send you out of control. However, the CDL being engaged fixes this problem.

p76rangie wrote:Mick, the traction control will switch off if you start it with the centre difflock engaged, so make sure you put a switch in to disconnect the diff lock sensor when starting. Just using traction control when reversing down a hill can cause the front wheels to lock up and send you out of control. However, the CDL being engaged fixes this problem.

Appreciate the tip

The best mod for the Disco2 is the CDL activation, though as said the wire that comes out of the CDL needs to be switched to maintain ETC on startup. A very easy mod. You should get this done first, otherwise even with lockers the front will tramp and spin you around. The CDL is not available in 2002 I think until the current MY03 face, the 99-02 models just require some way to enguage it. I have a $440 link from Bruce Davis Performance Landies to do the trick.

With lockers if the locker(s) are enguaged the ETC becomes redundant on that axle, if the locker(s) disenguaged then the ETC will resume working as normal on that axle.

Sometimes even when fully locked the ETC light will still come on, though that is just the system reacting to the differing wheel speeds caused by flex in the axles while working.

Another thought, with CDL and ETC it is loosely comparable to a regular 4WD with a rear locker. In some situations its slightly better, in some its slightly worse.

The centre diff lock switch reactivated helps alot reversing down hills as previosly mentioned.
I think that a good senario would be centre difflock switch and rear cross axle difflock as with setup you wouldnt have the bad steering charectristics of a front diff lock and the tracton control would only be working on one front whhel at a time which should overcome some of the short falls of the original system that had to work on all four wheels.
Drive it like this for a while before putting in a front locker.
Ta
Michael

I reckon it helps a lot everywhere, as said LR should never have removed it. The CDL prevents a hell of a lot of wheelspin and stops the front spinning and tramping on a climb.

Bloody hell now I'm confused. Lets see if we can put this in even more simple terms.

Differentials are designed to distribute even amounts of engine torque to both axles while allowing the axles to turn at different speeds while cornering. Once one wheel breaks traction (lifts off the ground or spins on loose surface etc) the engine torque is delivered to that wheel as it offers the least resistance and the other one, the one with traction, stops.

Centre diffs are no different. Instead of turning axles they turn drive shafts and allow them to run at different speeds as you turn corners because the front wheels always follow a different path to the rear.

If either your front or rear wheels start to spin the opposite drive shaft just stops as the engine torque once again takes the path of least resistance. Savvy? By locking the centre diff you guarantee that both the front and rear drive shaft will turn at the same rate. That way if the front start to spin the rear keeps driving as long as it has traction.

By fitting a front and rear differential lock ALL FOUR WHEELS will continue to drive at the same rate regardless of whether one or two are in the air.

Traction control works by sensing speed differences between the wheels. When one wheel starts to slip and spin faster than the rest the traction control grabs that wheel with the brake stopping it from spinning momentarily and this action forces the power to the opposite wheel, the one with traction.

The same principle has been used on tractors for years. Ever wonder why they have two brake pedals on tractors? Now you know. If one wheel starts spinning the driver jumps on the brake for that wheel and the drive goes to the one that wasn't spinning.

Welcome newbe. Hope we have not confused you too much.

For all your 4wd mechanical needs on the Goldie go and talk to Sean at South East QLD 4x4 in Brendon Drive Nerang.

Andy