DESCRIPTION & OPERATION
The Borg-Warner 44-06 is available in both Mechanical Shift On the Fly (MSOF) and Electronic Shift On the Fly (ESOF) versions. Both types utilize an internal electromagnetic multi-disc clutch assembly to shift transfer case from 2WD High to 4WD High. Transfer case operation (2H to 4H and 4H to 4L) is conducted either by a manually operated lever or electric motor that move internal shift forks. See Fig. 1 .
Once the shift lever (MSOF) is moved to 4H position or mode switch is turned (ESOF) to 4H position, the Generic Electronic Module (GEM) energizes internal clutch to lock transfer case. Shifting between 2H and 4H can be done at speeds up to 55 MPH, but vehicle must be stopped with brake pedal applied and transmission in neutral to be shifted between 4H and 4L.
Generic Electronic Module (GEM) is mounted on fuse block below left Side of dash panel.
Brake On/Off (BOO) Switch
The PCM receives a signal from the BOO switch when the brake switch is operated. The GEM and PCM are linked by a communication network. When shifting into or out of LOW range, the GEM requires brake pedal to be depressed.
Clutch Pedal Position (CPP) Switch
The PCM receives a signal from the CPP switch when the clutch pedal is depressed. The GEM and PCM are linked by a communication network. When shifting into or out of LOW range, the GEM requires clutch pedal to be depressed.
4WD Mode Switch
Instrument panel mounted switch sends input signal to GEM pertaining to commanded transfer case range.
Throttle Position (TP) Sensor
The TP sensor is a potentiometer mounted to the engine throttle body. The PCM receives a signal from TP sensor relaying throttle plate position. The GEM and PCM are linked by a communication network. Signal is used by the GEM to control A4WD clutch.
Transmission Range (TR) Switch
The TR sensor is a digital type. The PCM monitors a series of step down resistors in TR sensor that act as a voltage divider. The voltage signal corresponds with position of transaxle range selector lever. The GEM and PCM are linked by a communication network. The TR sensor also contains neutral/start and backup light circuits. Malfunction of TR sensor or non-confirmation of transmission being in neutral may cause transfer case not to shift. Improper transmission shifting or shift selection and no engine cranking may also result.
Vehicle Speed Sensor (VSS)
The VSS is a magnetic pickup that sends output speed signal to the PCM. The GEM and PCM are linked by a communication network. When shifting into or out of LOW range, the GEM requires vehicle speed to be less than 3 MPH.
Transfer Case Clutch Relay
Pulse width modulated signal operated relay that operates internal electromagnetic clutch.
4WD Shift Motor Relay
Actuates electric shift motor mounted to transfer case. Shift motor drives a rotary cam which moves mode fork and range fork inside transfer case.
4WD/2WD Vacuum Solenoids
Both solenoids are attached to upper RH side of engine compartment dash panel. Solenoids alternately route vacuum to vacuum motor which engages/disengages center axle disconnect collar in front axle assembly. See Fig. 1 .
Thursday, January 1st, 2009 AT 7:11 PM