Thread: Traction Control on 11MY Defenders

Originally Posted by Xtreme

Thanks for reply.
So if engaging CDL on corrugated road reduces 'the shock loading back through the gears ...... " would this not also be the case when travelling on any gravel road where traction is likely to be lost, however infrequently, and therefore be a reason FOR engaging CDL in such circumstances?

He was referring to the specific case of corrugations being a potential cause of failure in the transfer case where the drive chain is weakest. The surface, I think, of the corrugated roads he is referring to are mostly gravel. But, a gravel road or may not have them, and the surface can vary significantly, as has already been said. You cannot extrapolate his conclusion to therefore include every gravel road.

Again. The only positive reason for not having the CDL engaged is the risk of binding up, although I think that speed was mentioned too. Binding up will only occur in those cases where traction cannot be lost. Therefore CDL can be engaged at any other time when traction is lost.

The choice is then when to use it. The are many models and each has their own idiosyncrasies. Add to that the surfaces over which the vehicle is driven, the wetness/dryness, the condition of the vehicle itself, and lots of other factors. When to use the CDL is up to the driver and their expertise.

Alan

Originally Posted by Xtreme

Thanks for reply.
So if engaging CDL on corrugated road reduces 'the shock loading back through the gears ...... " would this not also be the case when travelling on any gravel road where traction is likely to be lost, however infrequently, and therefore be a reason FOR engaging CDL in such circumstances?

I don't know if anyone has ever lunched a centre diff just from pounding around in high range, but how you'd measure a cumulative effect of shock loading or overloading on gears and bearings I'm buggered if i know.

We've all heard stories of people exploding the centre diff in low range though, all that torque going through some small side gears just spits pieces everywhere, this is less likely to happen in high range as theere is far less torque multiplication.

What i was thinking out aloud about was I remember my old kart engine builder built rally cars in another life time (he was sponsored by GMH for a number of years) and they always told me that the shock loads from jumps and corrugations was pretty high back through the transmission and IIRC was worse if you back off at the wrong times, ie. the peak of the bumps as it loaded the gears on the coast side and that usually broke gearboxes.