Automatic disconnecting differential actuator, ADD allows for engagement of 4X4 on the go, a flange is mounted on the front hub which is splined onto the axle shaft connected to a side gear shaft on front differential. Locking hubs are not used with ADD.
When the transfer case is shifted into 4wd, ADD is shifted into 4wd by operation of ADD actuator electric motor. ADD actuator engages clutch sleeve intermiediate shaft in front diff. and side gear shaft providing 4wd operation. When vehicle is in 4wd an indicator light on the dash is lit.
Operation of the transfer indicator switch or 4wd switch completes the ground circuit which allows the ADD relay to operate, when the relay operates, voltage is supplied to add actoator! If it was me I would chech these switches and relay first!
Saturday, November 10th, 2007 AT 4:26 PM