Sand Setting on Evoque

So what your saying is I shouldn't be using it on a windy road bc of the 4wd lock?

What happens when you get the 4wd lock is Transmission Wind-up, on a Defender you get this when you use the diff-lock on road because there is no slip across an axle as you go round corners, in off road situations windup can be released by driving on a loose or slippery surface - unless you take you car into a park in town and drive on the grass (preferably wet grass! ) to release the windup then you will kill your transmission eventually in the Evoque? In Evoque it is the viscous coupling that gets locked as a diff lock.

(08-05-2012 06:35am)XFullFatTim Wrote:  What happens when you get the 4wd lock is Transmission Wind-up, on a Defender you get this when you use the diff-lock on road because there is no slip across an axle as you go round corners, in off road situations windup can be released by driving on a loose or slippery surface - unless you take you car into a park in town and drive on the grass (preferably wet grass! ) to release the windup then you will kill your transmission eventually in the Evoque? In Evoque it is the viscous coupling that gets locked as a diff lock.

Please ellaborate on this.. Slightly confused and interested on how the lock works? Is this te same principle when in Dynamic mode?

Your Evoque, and all 4WD Evoques, use the viscous coupling to determine how much power to send to the rear wheels as well as the fronts. In normal driving something like 95% of the drive goes to the front and 5% to the rear, the viscous coupling can change this to be something like 95% rear and 5% front depending on traction, additionally it can send power from side to side using the ABS and TC to the wheels with most grip.
Launch control, as used in sand mode "locks" the VC and sends equal power to all the wheels. In addition to the VC Evoque and Freelander2 have an intermediate reduction drive, (aka IRD) which acts like a differential. When you go round corners as you know the inside wheels rotate at a differ speed to the outside wheels ( thanks to the differential in the axle) by locking you remove this ability for the wheels to rotate at different speeds, and this manifests itself as damage to the drive system. If you get transmission wind up then there are 2 options to unwind it if you haven't already done damage - reverse round a few corners (inconvenient) or find a slippery surface like wet grass and you might hear the wheel slip or a bang, you hope it isn't a bang!
Try googling transmission wind up or better still take yourself on a Land Rover Experience course as they have a very nice video that explains how diffs, diff locks and limited slip differentials work and what transmission wind up is and how to avoid it.
Sorry I cannot explain very clearly, maybe Richard will do a better job.

Really interesting and useful comments I still cannot understand why the TR control as it is such an important function of the vehicle is not given more in depth description/ instruction/ warnings in the owners manual. I have experimented with it on my Freelander and totally unaware that in sand setting it is locking it into 4 wheel drive does it (TR) disconnect over a set speed as I have carried on driving forgetting it still in sand setting .

Thanks Tim - interesting, so the IRD is the bit of the drive train that really differentiates the Freelander and Evoque from say the Audi Q3/Q5 Quattro that also use a Haldex coupling. Until today I'd never seen a convincing explanation as to why the Freelander and Evoque are so much more competent off-road than competitive vehicles that play in the same market. Thanks.

I understand this to a degree, but am puzzled as to what actually happens, in mechanical terms, if you 'unwind' the transmission. Is it just a matter of destressing the components, assuming that they have not already been damaged?

Also, while I follow how a fixed four-wheel drive or locked differential between the front and rear could cause mechanical damage, would not an intermediate viscous coupling be able to cope with the slight difference in rotational speed between the axles?

The Freelander 2 didn't used to have sand launch, I think it is something new with Evoque. IIRC 2010 or 2011 RRS, D4 and FFRR have it too. I'm not an engineer and don't fully understand diffs and locking diffs but I do know I must never drive my Defender any distance on a metalled road in diff locked mode.

As an aside Volvo Cross-Country Estate cars and the XC90/60 used to require all 4 tyres to be changed at the same time because the slightly different rolling radius of a new tyre over a well used one could cause the same problem with the transmission, I don't know how they got round it, or if the have!

No harm in having a little play around with the TR just to feel how each setting alters the car, but I wouldn't abuse it. Best to have a day out at a LRE centre, it's great fun and the instructors know there stuff. I've done FFRR, RRS, Fl2, RRE and full day in the Defender.

(08-05-2012 05:48pm)J77 Wrote:  No harm in having a little play around with the TR just to feel how each setting alters the car, but I wouldn't abuse it. Best to have a day out at a LRE centre, it's great fun and the instructors know there stuff. I've done FFRR, RRS, Fl2, RRE and full day in the Defender.

It's always better to bugger up someone else's car
It's like the saying "no car goes as quick as a hire car"