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Discussion Starter · #1 ·
i'm planning to buy a 2004-2006 sorento xs or xe.
i want to have best capability off-road and in snow.
although i like the high spec of the xs i'm wondering if it may not be as good as the xe in above conditions since the torque-on-demand xs does not lock into 4wd in high range (as does the xe) but only auto engages as required which i wonder is good enough. I know you can lock into 4wd low with the xs but you may not want to do that all the time in snow or offroad. i'm wo ndering if the TOD xs would maybe engage too late or not stay engaged properly in tricky conditions as opposed to the fully locked 4wd xe.
does anyone have experience/advice to give me .
it's a pity the xs does not have an extra option - 4wd high lock as well as 4wd auto and 4wd low.

3 Posts
I've had plenty experiance with a 2005 XS on snow with Vredestein Wintrac 4 Extreme tyres.
You never want to use low range, under any circumstances in snow. Auto works amazingly well, you simply don't need to lock 4WD.

Without snow tyres though, you're the same as everybody else and will need chains. 4WD doesn't help going downhill.

235 Posts
I conclude...
My XS Manual would pull through all the snow and ice, but you need the correct tyres..i had no issues.

I have added an explanation into the differences...

Re: explanation of locking (2wd, 4hi 4lo) ?

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The Sorento, like most true 4wd's has a conventional gearbox, but on the back of that is a transfer gear box which splits the drive to the rear axle for 2wd, or to the front and rear axle for 4wd. As well, a reduction gear can be engaged to give low range gearing in 4wd.

As you say, 2wd is just that, the rear two wheels are driven, with drive to the front wheels disconnected by a clutch in the transfer gearbox. Also there is a compressed air driven clutch in the front differential which allows the front wheels to 'free wheel'. This saves on fuel and tyre wear as the differential and front driveshaft are not turning. The air compressor is turned on when 4wd is selected. The air pressurises the differential housing to about 5lbs/sq in to engage the clutch.

4wd drives all 4 wheels through the main gearbox and transfer box. The front and rear wheels have to turn at the same speed.

4wd Low drives all 4 wheels as above, but the reduction gear is engaged to give more torque for difficult conditions.

It is possible to change between 2wd and 4wd on the move just by moving the selector knob, but you must be stationary to engage 4wd Low.

Also remember not to drive in 4wd on hard surfaces such as bitumen roads, as this can cause damage to the transmission. The reason for this is that when turning a corner, the front wheels travel further than the rear. If they are locked together in 4wd, something has to give. Either the tyres skid or something breaks in the transmission.

Vehicles designed for constant 4wd have a differential in the transfer box to allow the front and rear driveshafts to turn at different speeds so avoiding the problem.<?: prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" />

That sums up the conventional 4wd system.

The TOD (Torque-on Demand) system is a little different.
This system uses the wheel rotation sensors from the Anti-Skid Braking system to detect when the rear wheels are turning faster than the front wheels. If the rear (drive) wheels are turning faster, the system assumes the wheels are slipping and automaticaly engages the front wheels to give 4wd and so improve traction.
This works fine on snowy roads and icy driveways, but is not so good off road in mud or soft sand. The reason is that by the time the system has responded, the rear driving wheels are already bogged down. Also the system tends to 'hunt' in variable off road conditions.<BR style="mso-special-character: line-break">People think just because it has 4wd it will go require the correct tyres for these conditions, not plain road tyres.

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