Thread: Centre Diff Lock

I always engage the centre diff lock (CDL) when on technical tracks.

Please correct me if this wrong; Worst case:

CDL not engaged: 1 wheel turns
CDL engaged: 1 wheel turns at front, 1 wheel turns at back
Rear Diff Locker engaged: Both wheels turn at back (if you have one)
Front Diff Locker engaged: Both wheels turn at front (if you have one)

Originally Posted by Naks

As soon as you leave tar, engage CDL and reduce tyre pressures.

X2 I just had my trans case rebuilt as a consequence of previous owner not locking ctr diff enough on gravel, or basically anything that wasnt sealed. Flogged out ctr diff bearing and thrust washers as its not designed to be loaded with uneven drive while off road. Was told its better to use it too much than not enough. Rebuild also made huge improvement to drivetrain backlash and hard gear changes.

Originally Posted by Beckford

I always engage the centre diff lock (CDL) when on technical tracks.

Please correct me if this wrong; Worst case:

CDL not engaged: 1 wheel turns
CDL engaged: 1 wheel turns at front, 1 wheel turns at back
Rear Diff Locker engaged: Both wheels turn at back (if you have one)
Front Diff Locker engaged: Both wheels turn at front (if you have one)

Yes,
Yes,
If you have CDL disengaged, but a front OR rear locker engaged, then one of the wheels on the unlocked axle will turn and you will be no better of than having no locker.

one Locker + CDL engaged, then you will aways have at least 3 wheels turning.

F+R locker but CDL disengaged, then only 2 wheels on one of the axles turning (again worst case - e.g. when climbing a steep hill, drive will go to the front as it will have less load).

iv tryed with and without on dirt rds,, if i feel it sliding about and that,, i just slow down

i only put cdl in if i recon theres gona be a chance of wheel lift, and if it looks hectic enof then the locker gose on,

Originally Posted by isuzurover

Conversely, I (and many others) engage my rear locker (as well as CDL) when going down steep slopes or traversing sidslopes offroad.

With the CDL engaged, if you get crossaxled while going downhill then the vehicle will race forward. With no CDL, only one wheel has to lift for the same to happen.

With CDL+rear locker, as long as at least 1 rear wheel is on the ground, you will have an even rate of descent and the vehicle will track straighter.

(n.b. This is on a vehicle without HDC/ETC - however the same should still apply).

The Defender doesn't have HDC anyway...

Without the locker, lifting a wheel will cause the wheel to rotate backwards, the vehicle will surge forwards and when the wheel comes back in contact with the ground it has the potential to damage the axle.

In this type of scenario, you are taught to feather the brake slightly as that will help prevent the wheel from rotating backwards.

...and FWIW - I'll engage CDL when I'm on any loose surface. The important bit is to make sure you disengage before you hit the black stuff!!

M

Oh well, I'm the odd one out (again) as I only use the CDL when i need it. ie. real 4WDing where one may lift a wheel or spin a tyre.

portafilter, I drive loose gravel all the time and never bother with the CDL and the car has 280,000km ATM.
The t/case is still holding up and drives ok (which I'm surprised at as it had different tyre sizes front/rear when I bought it with 76,000km on the clock. The t/case fluid was black from being overheated)

I can imagine burning up the centre diff if the CDL isn't used in really loose/muddy conditions or lifting wheels and the driver just keeps the right foot into the firewall but on a normal gravel/dirt/shale road ?

That makes two of us Rick.

I had been led to believe that what destroyed the centre diff was either the front prop shaft and rear prop shaft turning at significantly different speeds for a considerable time (eg one wheel allowed to spin a lot) or the two prop shafts turning at slightly different speeds and suddenly being made to turn at the same speed (eg a spinning wheel suddenly getting grip).

Neither of those things happens if you drive sensibly on dirt roads.

Rick and vnx205

I suppose the consensus is that - it can't do any harm to lock the CDL whenever you drive on loose surfaces...