Thread: Traction Control on 11MY Defenders

Interesting discussion this.

I see no one has mentioned the main reason for NOT driving with a CDL on, in any case. That of the risk of binding up of the transfer case. Other than that there is no particular reason for disengaging it, but of course every situation and vehicle is going to be different and have its own handling characteristics. I am not advocating having CDL engaged when not specifically required however.

I only engage CDL in the Stage 1 when I am going to need the added traction it affords. When running down hill or across sidlings I have it disengaged unless there is a specific need to have it engaged, for example yesterday a particular sidling I had slipped into (off the track) that was composed of rounded volcanic river rocks bound by loose clay and gravel. I tried twice to gently climb back onto the track without CDL but needed the additional traction to get the job done. The effect on downhill runs and sidlings is for the back to swing around down the slope as the wheels turn regardless of the amount of traction they have. Disengage CDL and each wheel will find its own speed and one is not exerting much power anyway, so there is going to be little wheel spin.

Most D2's have TC and ABS so unless there is a specific need there is no reason to have CDL engaged. As the pommie postings illustrate, TC emulates the effect of CDL in most cases and it is only in the more extreme situations or where the wheels are revolving too slowly for TC to respond that you might need CDL engaged (which is probably also the reason that the D2 behaves well on metal roads, mentioned earlier, and mine certainly does). I have seen TC engage even at very slow speeds with very minor shifts in wheel spin in my D2, so that effectively rules out 95%+ situations where you might want to use CDL.

Originally Posted by BigJon

Personally, if I am driving fast on a dirt road and I happen to get airborne, I lift off the throttle while in the air so that I don't have the wheels spinning much faster than the "ground speed" when I land. In that instance it doesn't make any difference whether the centre diff is locked or not.

Absolutely, either bitumen or dirt.

The other thing is to always hold the wheel straight and correct after landing, otherwise it could get very nasty with some lock on when hitting terra firma.

Scenario - Straight, flat, heavily corrigated gravel road, CDL engaged or disengaged?

Most of the discussions to date have been in relation to cornering etc so I would be interested in opinions on the above circumstances where rapid and repeated loss of traction occurs.

Originally Posted by Xtreme

Scenario - Straight, flat, heavily corrigated gravel road, CDL engaged or disengaged?

CDL locked.

Originally Posted by disco2hse

I see no one has mentioned the main reason for NOT driving with a CDL on, in any case. That of the risk of binding up of the transfer case.

That only occurs when driving with the CDL locked on a sealed surface. IME, on dirt/gravel, there is enough 'give' in traction to not bind the transfer case. If it does bind, quick reverse for 2-5m should do the trick.

Originally Posted by disco2hse

I see no one has mentioned the main reason for NOT driving with a CDL on, in any case. That of the risk of binding up of the transfer case. Other than that there is no particular reason for disengaging it,

That is my criteria/reasoning. When I am on a surface where there is no chance of windup occurring, I usually engage the CDL.

The centre diff is the weakest, most fragile part of the LT230. IMHO keeping the CDL engaged when offroad on loose surfaces can only help prolong the life of the centre diff.

EDIT - however I don't engage the CDL on bitumen - wet or otherwise.

Originally Posted by Naks

That only occurs when driving with the CDL locked on a sealed surface. IME, on dirt/gravel, there is enough 'give' in traction to not bind the transfer case. If it does bind, quick reverse for 2-5m should do the trick.

Umm, yeah. That's the point I was making.

As for reversing, that is likely to cause further damage if the transfer case gearing is already locked up. Disengaging the CDL while the gearbox is in neutral or between hi and lo ratio is safest.

ok,, so now i can say how it was after driving a defender WITH the new ABS sys, it was in a 90 so they are abit twitchy on wet roads as is,

the sys is very fast to react, much better then the sys on the d2 but not as good as the freelander 2, when going around a known very slippery roundabout,

for a cross up situation without cld, it did stop as soon as the front lifted and took a fear bit of skinny pedal b4 it had enough go to move ford, dident feel much better then the current sys, just alot smother when activating,

but as you'd expect cld ON and over the same rut, the car walked it and the tc keeped things moving like you'd expect, left at engine idle and the engine compensated well for the tc activating and reving up slightly

this was on very wet grass over a prity big gutter on the side of a rd, and prity slipry, the new tyres seemed ok but i think id still want the old grabbers back on

just my thorts after driving one,

Originally Posted by Xtreme

Scenario - Straight, flat, heavily corrigated gravel road, CDL engaged or disengaged?

Most of the discussions to date have been in relation to cornering etc so I would be interested in opinions on the above circumstances where rapid and repeated loss of traction occurs.

Originally Posted by Naks

CDL locked.

[snip]

I'd go along with that, the shock loading going back through the gears is pretty high as you hit each corrugation at speed so anything to minimise or avoid the impact on the centre diff gears is good.
As Ben said, it's the weakest part of the t/case.