A method of transitioning between two intake valve lift states while providing constant engine torque output comprehends the steps of receiving a lift change request from an engine control device, determining the current phase angles of the camshafts, and determining whether the intake and exhaust camshafts are at transition positions. The transition positions are experimentally or empirically determined combinations of operating conditions that result in constant engine torque output before and after the intake valve lift transition. If they are, an appropriate, i.e., low to high or high to low cam lift state transition of the intake valves occurs. If they are not, the cam phasers move the intake and exhaust camshafts to transition positions. When the cam phasers have moved the intake and exhaust camshafts to the transition positions, i.e., positions of constant engine torque output, the intake valve lift transitions from high to low or low to high.

An apparatus for fixing a sticking damper clutch may include: a transmission controller configured to determine whether a damper clutch sticks, using engine controller information received from an engine controller and damper clutch status information of the damper clutch; and a hydraulic pressure controller configured to fix the sticking damper clutch according to the determination result of the transmission controller.

A hydrokinetic torque-coupling device for coupling driving and driven shafts. The torque-coupling device includes a casing having a locking surface, an impeller wheel and a turbine wheel hydrodynamically drivable by the impeller wheel, a lockup piston axially movable toward and away from the locking surface, a friction disc including a generally radially orientated friction ring and at least one driving tab, and a torsional vibration damper comprising the friction disc, elastic members and an engagement member elastically coupled to the friction disc through the elastic members. The friction ring has a radially outer peripheral surface defining a centering surface of the friction disc. The engagement member includes at least one centering tab extending toward the friction ring and having a centering surface disposed adjacent to and facing the centering surface of the friction disc to center the friction disc with respect to the engagement member of the torsional vibration damper.

A vehicle sailing stop control method is provided for a vehicle including a friction engagement element disposed between a traveling drive source and drive wheels, a torque converter disposed between the friction engagement element and the traveling drive source, and including a lock-up clutch for which a power transmission amount is controlled based on hydraulic pressure, and a hydraulic pressure source that can supply the hydraulic pressure while the traveling drive source is stopped. The vehicle sailing stop control method includes: performing sailing stop control so that coasting is performed by cutting off power transmission of the friction engagement element and stopping the traveling drive source upon a sailing stop travel condition being established; and, during coasting by the sailing stop control, placing the lock-up clutch in a power transmission state in which the hydraulic pressure is applied to the lock-up clutch.