Thread: Centre Diff Lock

Originally Posted by Drew90

Hey Everyone,

Had read some conflicting opinions about when to use and when not to use the central diff locks. Currently I only use them when I need to, but have heard people talking about having them on all the time over slippery terrains. What's the proper story?

Cheers

It is largely a matter of personal opinion/preference.

My view is that engaging the CDL as soon as you leave a hard packed surface will reduce wear and heat buildup in the T-case and centre diff.

Spinning one wheel offroad will rapidly wear the centre diff and/or degrade the t-case oil.

If I am driving along hard packed dirt roads I won't bother - or if I am going on and off bitumen repeatedly then I won't bother.

Hi Drew,

Land Rover's advice is to engage the Central Diff-lock as soon as you are no longer on a fixed/hard surface (eg. bitumen).

The logic behind this is because it improves the vehicle grip and hence safety - however these days the advantage has been negated somewhat by the advent of traction control.

Originally Posted by isuzurover

It is largely a matter of personal opinion/preference.

My view is that engaging the CDL as soon as you leave a hard packed surface will reduce wear and heat buildup in the T-case and centre diff.

Spinning one wheel offroad will rapidly wear the centre diff and/or degrade the t-case oil.

If I am driving along hard packed dirt roads I won't bother - or if I am going on and off bitumen repeatedly then I won't bother.

wot he said, except that I also turn it of when I am going down a steep incline and I am letting the wheels find their own traction in first gear Lo, and when I am going along a sidling because I find that sometimes the rear wheels can screw themselves down the slope.

Originally Posted by disco2hse

...except that I also turn it of when I am going down a steep incline and I am letting the wheels find their own traction in first gear Lo, and when I am going along a sidling because I find that sometimes the rear wheels can screw themselves down the slope.

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).

That's if you have a rear locker

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).

Originally Posted by disco2hse

That's if you have a rear locker

True, however HDC/ETC should perform a similar function???

I also have tried CDL vs no CDL down steep (cross axley) hills, and CDL engaged is much safer and more controlled IME.

That's if you have HDC/ETC

Originally Posted by isuzurover

True, however HDC/ETC should perform a similar function???

I also have tried CDL vs no CDL down steep (cross axley) hills, and CDL engaged is much safer and more controlled IME.

Well, these things are related to the vehicle and many other factors like how rocky, muddy, slippery, etc. For most places where I need to use first lo CDL and going down an incline it is too risky because I have found the wheels tend to lock up (front and rear) and I prefer to keep them turning. That means if they are all turning at different speeds then no problem, at least they are turning and I am not skating. But I accept that others will have different experiences

I guess in answer to the OP, you need to know your vehicle and make your choices accordingly. There is no one rule.

Originally Posted by disco2hse

That's if you have HDC/ETC



Well, these things are related to the vehicle and many other factors like how rocky, muddy, slippery, etc. For most places where I need to use first lo CDL and going down an incline it is too risky because I have found the wheels tend to lock up (front and rear) and I prefer to keep them turning. That means if they are all turning at different speeds then no problem, at least they are turning and I am not skating. But I accept that others will have different experiences

I guess in answer to the OP, you need to know your vehicle and make your choices accordingly. There is no one rule.

You are talking about muddy/greasy hills mainly? Certainly a different kettle of fish to rocky/rutted (but dry) hills.

For greasy hills I have always selected 1st low +CDL and then accelerated if the wheels start to lock up.

Don't you find that the vehicle tries to pivot around if one front wheel locks up with CDL disengaged?