Mj__Smith's question concerning his Haldex got me thinking. How does Volvo's Haldex system actually work? I mean mechanically. With the ABS system? Clutch pac? If so, is it electronically or fluid activated? What does it take to engage the rear wheels? How much slippage or is it a true AWD system? Are the rear wheels along for the ride unless needed?
Can torque be transferred between the rear wheels (side to side)? How is this done? Between the fronts?
Several years ago the Haldex systems was suppose to be improved. What, exactly, did that mean? Quicker engagement? How?
I understand 4x4 and AWD systems in general, but not Volvo's system. I'd like a 101 primer, or a place to look for the answer. Thanks.