Genuine Toyota Differential

Toyota 4Runner Differential Parts Questions & Experts Answers

• Q: What is the Automatic Disconnecting Differential (ADD) for 4WD models and how is it removed and installed on 2003 through 2009 Toyota 4Runner?

  A: The Automatic Disconnecting Differential (ADD) system is responsible for connecting the power flow through the left Axle Shaft in 4WD mode and disconnecting it in 2WD mode. While ADD offers convenience in selecting 2WD or 4WD without dealing with locking hubs, it increases wear on CV joints, dust boots, and certain axle and differential components that rotate even in 2WD. Regular inspection of CV joints and boots is recommended for ADD-equipped vehicles. If issues arise during shifting into or out of 4WD, it's advisable to have the ADD system checked by a qualified repair shop or dealer service department specializing in 4WD vehicles. For differential carrier removal, begin by loosening the wheel lug nuts, and raising and securely supporting the vehicle on jack stands. Remove engine splash shields, and driveaxles, and drain the lubricant from the differential. Disconnect the driveshaft from the front differential and support the front end with wire. Proceed to remove the front stabilizer bar, brackets, front wheel speed sensors, and front tie rod ends, and separate the lower control arms from the steering knuckles. Disconnect the breather tube bracket, detach the fasteners retaining the vacuum tubing bracket, unplug the actuator electrical connector, and detach the actuator vacuum hoses. Remove the tube and wire harness assembly from the differential. Support the differential with a transmission jack or floor jack, remove the differential rear mounting nut and the two front mounting bolts/nuts, and lower the differential. For installation, follow the reverse order of removal. Refill the differential with the appropriate lubricant and tighten the lug nuts to the specified torque. To remove the ADD actuator, raise the vehicle and support it securely on jack stands. Remove the splash shields and the four retaining bolts. Take out the actuator. Before installing the actuator, clean off the old RTV sealant from the mating surfaces of the differential and the actuator, and apply a thin bead of new RTV sealant to those surfaces. During installation, tighten the bolts according to specifications, and reverse the steps of removal.