2-Speed Torque On Demand Transfer Case with 4HI-LOC

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

2-Speed Torque On Demand with 4HI-LOC system consists of the following components:

4x4 Switch Module (MSS)
TCCM (located near the passenger kick panel)
IWE (integrated wheel end) solenoid (located on cowl near brake booster)
(2) IWE vacuum actuators (one on each front hub)
(2) IWE clutch rings (one on each front hub)
4WD mode indicators and messages in the IPC message center
Transfer case with shift motor and high capacity clutch

Vehicles equipped with the 2-speed torque-on-demand with 4HI-LOC system can operate in 2WD (2H), 4WD AUTO (4A), 4WD High (4H), or 4WD Low (4L). 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 is in NEUTRAL.

The transfer case is equipped with an electronically controlled high capacity clutch which is located inside the transfer case. The clutch varies torque to the front driveline in 4WD AUTO (4A) mode. In 4WD High (4H), or 4WD low (4L), torque is split equally between the front and rear axles.

The transfer case is shifted electronically based on the 4x4 Switch Module (MSS) input.

For additional information, refer to: Four-Wheel Drive Systems - System Operation and Component Description .