4L Operation

4L turns on when you select SLOW CLIMB. It provides electronically locked four-wheel drive power to both the front and rear wheels for use on low traction surfaces, but does so with an additional 2.64 gear reduction for increased torque multiplication. Intended only for off-road applications such as deep sand, steep grades or pulling heavy objects. 4L does not engage when your vehicle is moving above 3 mph (5 km/h); this is normal and should be no reason for concern.

Shifts to and from 4L can only be made below 3 mph with the transmission in Neutral. When performing this shift, wait until the 4x4 Shift in Progress message disappears in the IPC before moving the selector lever back to Drive. If the vehicle speed or transmission range is not within parameters, the message center will indicate the necessary action needed to complete the shift.

In 4L:

• The ATCM sends a 4L mode status on the HS-CAN2 via the GWM to the TCCM on the FD-CAN (4x4_SW = 4WD_LOW).
• The TCCM outputs a 97% duty cycle to the clutch field coil (4WD_CLUTCH_OUTPUT # = 97.0%).
• The shift motor is in the full CW position. Refer to TRANSFER CASE SHIFT MOTOR STATUS  in this procedure for further information.
• 4L is displayed in the message center.