Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Transfer Case
Electronic Shift-On-The-Fly (ESOF) System
The ESOF transfer case system consists of the following components:
- MSS, located on the instrument panel
- Transfer case assembly (includes shift motor and synchronization clutch)
- TCCM
- Vacuum operated front locking hubs
The electronic shift transfer case is a 2-piece aluminum design. The unit transfers engine power from the transmission to the front and rear axles. Vehicles equipped with an ESOF system allow the operator to choose between 2WD (2H) and 2 different 4WD modes. The transfer case is shifted electronically based on the MSS position. Under normal driving conditions, the transfer case is in 2WD (2H), but when desired, the operator may shift into 4WD high (4H) or 4WD low (4L). The operator can shift between 2WD (2H) and 4WD high (4H) at any speed. When shifting into or out of 4WD low (4L) range, the TCCM requires that the vehicle speed is less than 5 km/h (3 mph) and the transmission in NEUTRAL.
The transfer case is equipped with a synchronizing clutch which is located inside the case. This clutch is used to synchronize the speed of the front driveline with the rear driveline during 2WD (2H) to 4WD high (4H) shifts. The transfer case is lubricated by a positive displacement fluid pump that channels fluid flow through holes in the rear output shaft.
Manual Shift-On-Stop (MSOS) system
The MSOS 4WD system consists of the following components:
- Manual shift lever
- Transfer case assembly
- Manual front wheel hub locks
The Manual Shift-On-Stop transfer case is a 2-piece aluminum design. The transfer case transfers engine power from the transmission to the front and rear axles. Vehicles equipped with the Manual Shift-On-Stop system allow the operator to choose between 2WD and 2 different 4WD modes. The MSOS 4WD system is engaged or disengaged by rotating the control for both front wheel hub locks from the FREE or LOCK position, then manually engaging or disengaging the transfer case with the floor-mounted shifter.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.