DESCRIPTION & OPERATION
The Automatic Free-Wheeling (AFW) system replaces free-wheeling hubs and allows the vehicle operator to select 2WD or 4WD by means of a center differential lock switch on instrument panel and a4WD/2WD shift switch on steering column lever. (Scheme 1)
Three different driving modes are possible: 2WD, 4WD FREE for higher speeds on paved roads and low traction driving), and 4WD LOCKED (for extremely slippery or soft surfaces, and ascending steep slopes).
The center differential lock switch and 4WD/2WD shift switch provide signals to the 4WD control unit. Based on inputs from these switches and other switches (change motor position switch, change motor limit switch, etc.), control unit activates one of 2 solenoids: either the "free" or the "lock" solenoid. Free and lock solenoids control a vacuum actuator, which operates a mechanical "dog" clutch located on the left side of the front differential. Dog clutch engages differential with axle shaft. (Scheme 2), (Scheme 3) and (Scheme 4).
