Pinpoint Test J : Four-Wheel Drive (4WD) System Functional Test: Notes

WARNING: This page is about a different car, the 2017 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Locator views for the vacuum lines and vacuum reservoir are located in Description and Operation. Refer to DESCRIPTION AND OPERATION . REFER to: Two Wheel Drive/Four Wheel Drive Systems for schematic and connector information.

Normal Operation

When operating in 4WD modes, the transfer case clutch is energized and both IWEs are locked. When in 4L mode, the transfer case low range gear set provides an additional 2.64 gear reduction. When operating in 2H mode, the transfer case clutch is de-energized and both IWEs are unlocked. The transfer case has certain amount of clutch drag which can cause the front driveshaft to spin even when in 2H mode."

Possible Sources

Transfer case and related components
IWEs and related components
Wheel/tire assemblies