DESCRIPTION & OPERATION
The transfer case uses a Shift-On-The-Fly system, which switches between 2WD and 4WD electrically by pressing the 4WD switch. (Scheme 2)and (Scheme 3). This system controls the following operations
- Connecting or disconnecting front output gear to and from front drive shaft via a motor actuator.
- Retrial of shift transfer front output gear, if not successful on first attempt.
- Connecting front wheels to or from front axles via vacuum actuator.
- Indicator light function.
- 4WD "OUT" signal to Electronic Hydraulic Control Unit (EHCU).
NORMAL OPERATION
Motor actuator is mounted on transfer rear case and is driven by signal from 4WD switch. After output gear is connected to or disconnected from front drive shaft, the condition of transfer position changes. Vacuum Solenoid Valve (VSV) is driven by signal from transfer position switch and vacuum actuator, connecting or disconnecting front wheels to or from front axles.
RETRIAL OPERATION
After switch signal is received by motor actuator, shift change begins. However, if shifting cannot be completed due to cold temperatures or high speed operation, system will attempt switching again after 2 seconds if shift change is not completed. Motor actuator will reverse its rotation for 1.2 seconds, then attempt to switch again. This process is repeated up to 3 times. The 4WD indicator light will blink rapidly to indicate shift switching is being attempted.
Scheme 2
Scheme 3
Note. Transfer case may be removed from transmission in vehicle.
Note. Before removing transmission and transfer assembly from vehicle, change transfer mode to 2WD using 4WD push button switch on instrument panel.