Principles of Operation

WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Manual Shift-On-Stop (MSOS) System

The MSOS system allows the operator to manually choose between 2 different Four-Wheel Drive (4WD) modes as well as 2-Wheel Drive (2WD) and NEUTRAL. For vehicles not equipped with ELD this system does not utilize a TCCM. The operator can switch between 2H (4X2), N (NEUTRAL), 4H (4X4 high) and 4L (4X4 low) at speeds below 5 km/h (3 mph). To engage or disengage 4L, the transmission should be in NEUTRAL to alleviate residual drag torque created by the engine. This system contains manual hublocks at the front wheel ends (hubs). The manual hublocks have settings of FREE and LOCK. Prior to shifting to 4H and 4L, the front axle must be coupled to the hubs by manually rotating the hublocks fully clockwise to the LOCK position.

The transfer case contains a non-synchronous clutch and Ford recommends that range shifts be carried out at or below 5 km/h (3 mph) to prevent excessive transfer case engagement noise. When the manual shift lever is moved to 4H, the mode sleeve is moved rearward, locking the drive sprocket and chain to the rear output shaft. Moving the lever to 4L causes the range sleeve to move further rearward and engage the planetary gear set. This causes the output shaft to turn more slowly than the input shaft, resulting in increased pulling capacity at the wheels. The shift lever also operates the Mode Indication Switch (MIS) in the transfer case, which triggers the IPC to illuminate the appropriate 4WD indicators in the IPC.

Manual Shift Transfer Case

The transfer case is a Borg Warner powertrain 2-piece aluminum transfer case design. The transfer case transfers engine power from the transmission to the front and rear axles. Under normal driving conditions, the transfer case should be in 2H, but when desired, the operator can shift into 4H or 4L. 4H and 4L modes are intended for use in slippery conditions, such as ice and snow, or in off road situations only. 4H and 4L are not to be used on dry pavement. The MSOS transfer case is shifted manually. The unit is lubricated by a positive displacement fluid pump that channels fluid flow through holes in the mainshaft.