Electronic Shift-On-The-Fly (ESOF) System

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.

The Electronic Shift-On-The-Fly (ESOF) system consists of the following components:

MSS
TCCM (located near the passenger kick panel)
IWE 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 synchronization clutch

Vehicles equipped with the Electronic Shift On-The-Fly (ESOF) system can operate in 2WD (2H), 4WD High (4H), or 4WD low (4L). When shifting into or out of 4WD (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 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 shifted electronically based on the MSS (Mode Select Switch) input.

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