Electronic Shift Transfer Case - Features and Operation
NUMBER: 21-06-00GROUP: Transfer Case
DATE: August 18, 2000
SUBJECT:
Electronic Shift Transfer Case Features And Operating Characteristics
MODELS:
2001 (AN) Dakota
2001 (DN) Durango
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A NV244 OR NV233 TRANSFER CASE.
DISCUSSION:
For the 2001 model year, the method of shifting either the new NV244 All Wheel Drive (AWD) transfer case or the new NV233 Part Time Drive transfer case has been revised. Instead of a manually operated shift lever to select a different shift mode or range, an electronic control switch is now used. The control switch will signal the Transfer Case Control Module (TCCM) to shift the transfer case into or out of the 4HI mode from either the 2WD or AWD mode. The control switch will also signal the TCCM to shift into and out of the 4H1 to 4LO range.
The transfer case control switch is located on the instrument panel. With the removal of the manual shift lever, the floor tunnel area is now less obstructed. The control switch is easier and more convenient to use. The capability to shift the transfer case electronically allows for future integration of the transfer case with other vehicle systems.
Like their predecessors in prior years, the new NV244 and NV233 transfer cases are not synchronized. This means that gear clash or clunk-like sounds may be noticed when transfer case shifting occurs. The gear clash/clunk-like sound will be most noticeable when shifting into or out of the 4LO range on automatic transmission equipped vehicles. Because of neutral drag on the transmission output shaft, by other components inside the automatic transmission, the output shaft may continue to rotate while the 4LO gears are being engaged or disengaged. A clash/clunk-like sound will be the normal result.
Shifting from the AWD or 2WD mode into the 4H1 mode, and vise versa, will normally occur within five seconds. Shifting between these two modes normally generates only a small amount of sound.
There is normally a delay of up to 15 seconds when shifting into or out of 4LO, but a delay of 30 seconds may be possible. The shift delay occurs due to the transfer case internal gears not being lined up, or when the gears are torque bound (spline locked) at the time of the shift. When this happens, the system stops and attempts to execute the shift command again. The system will attempt to shift five (5) times, at 5+ seconds per shift attempt. After the fifth attempt, the system must be reset. The reset is accomplished by re-selecting the original position for a couple seconds. After this, a new shift can be requested.
NOTE:
REFER TO THE APPROPRIATE 2001 DAKOTA OR DURANGO SERVICE MANUAL - GROUP 8E, ELECTRONIC CONTROL MODULES / TRANSFER CASE CONTROL MODULE, FOR A COMPLETE EXPLANATION OF THE SEQUENCE OF EVENTS AND TIMING DURING A SHIFT.
Once the shift has been made after the delay, the customer may become concerned with the 4LO gear clash/clunk-like sound, because it has occurred several seconds after the shift has been selected/requested. Though the gear clash/clunk was present with previous model year transfer cases, which used a manually operated shift lever to engage 4LO, the low range shift delay with the electric transfer case is new. The customer may not associate the delayed gear clash/clunk-like sound with their previous low range shift request/selection.
The transfer case control switch knob can select three mode/range positions only. For the NV244 transfer case those positions are: AWD, 4H1, or 4L0. For the NV233 transfer case the positions are: 2WD, 4H1, or 4L0 (Figure 1).
NOTE:
REFER TO THE APPROPRIATE 2001 DAKOTA OR DURANGO OWNERS MANUAL AND/OR 2001 DAKOTA OR DURANGO SERVICE MANUAL FOR DETAILED INSTRUCTIONS REGARDING PROPER SHIFT PROCEDURES.
The transfer case control switch knob CAN NOT be rotated to select the Neutral mode. A NEUTRAL MODE BUTTON must be depressed to select the Neutral mode (Figure 1). The customer may mistakenly attempt to rotate the control switch knob in an attempt to select Neutral mode. The Neutral mode MUST be used to flat tow the vehicle (i.e. when all four wheels are on the ground).
NOTE:
REFER TO THE APPROPRIATE DAKOTA OR DURANGO OWNERS MANUAL FOR DETAILED INSTRUCTIONS AND PRECAUTIONS REGARDING PROPER TOWING PROCEDURES.
POLICY: Information Only