VEHICLE AND METHOD OF CONTROLLING A VEHICLE, POWER TRANSFER UNIT AND METHOD OF CONTROLLING A POWER TRANSFER UNIT

摘要

A vehicle having a four-wheel-drive system including an auxiliary portion that has an auxiliary driveshaft and drive means between the auxiliary driveshaft arranged to releasably connect a second group of wheels to the driveline via a releasable torque transmitting device. The releasable torque transmitting device is operable to allow slippage of the input portion with respect to the output portions, thereby to vary an amount of torque that is transmitted to the second group of wheels.