ViperO6

Haldex.

Oaktree

The car is great in the snow at low speeds. I do not know much about Volvo's.

mmccall

The read drive is basicaly modulated in the rear diff. That's right! The rear drive shaft allways turns but no power goes to the rear wheels untin the diff locks up. The worst thing about that arrangement is that the rear end never has power unless the front breaks loose, therefore NO handeling benefits from the AWD system.

DRG

With Haldex, it is possible to improve this situation and gain handling benefits if so desired. In this system (used by the S60 AWD, as well as in all Audi/VW transverse-engine AWD setups), there is a slight gearing difference between front and rear differentials to force a rotational difference between input and output plates in the Haldex unit. This allows a pressure buildup even in the absence of actual wheelspin. A computer controlled pressure-relief valve prevents anything from happening until the computer says so, but the system is primed to engage very rapidly.

One consequence of this is that it should be possible to program the control computer to send some torque to the rear wheels in anticipation of a possible front-end traction issue, such as when accelerating or taking a curve, assuming there are the appropriate sensors in place. Auto mag test reports on the S60 AWD suggest that, unfortunatley, no handling benefits from the Haldex are noticed in this car. This type of control programming doesn't seem to be in place in the S60. It should, however, be possible to do so, to my knowledge.