Automatic Disconnecting Differential Actuator

WARNING: This page is about a different car, the 2002 Toyota Tundra and 2001 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.

Automatic Disconnect Differential (ADD) allows engagement of front differential from 2WD to 4WD while vehicle is moving. On vehicles with ADD, a flange is mounted on the front hub which is splined onto axle shaft connected to side gear shaft on front differential. Locking hubs are not used with ADD.

When transfer case is shifted into 4WD, ADD is shifted into 4WD by operation of ADD actuator electric motor. ADD actuator engages clutch sleeve with intermediate shaft in front differential and side gear shaft, providing 4WD operation. When vehicle is in 4WD, an indicator light on instrument panel will be illuminated.

Operation of transfer indicator switch or 4WD switch completes ground circuit which allows ADD relay to operate. When ADD relay operates, voltage is supplied to ADD actuator for 4WD operation.