 This ability to drive one of the rear wheels with more power (remember the row boat analogy) is accomplished through overdriving the rear wheels with respect to the front wheels.The Acura RL is designed with a third planetary gear set and clutch pack that are packaged into a so-called "Acceleration Device", which is bolted in front of the rear differential unit.The Acceleration Device allows torque to be passed to the rear wheels at a near one to one ratio, but in cornering situations, the Acceleration Device variably increases the torque passed to the rear up to 5%, depending on the cornering situation.