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Borg-Warner 4406 transfer case

How the Borg-Warner 4406 transfer case works

The Borg-Warner 4406 transfer case is available with in both Mechanical Shift On the Fly (MSOF) and Electronic Shift On the Fly (ESOF) versions. For the MSOF version, the driver uses a shift lever to move from 2H to 4H and 4H to 4L. For the ESOF version, the driver operates the 4WD mode switch and an electric motor moves the internal shift forks.

In both versions, whether the shift is conducted manually or with the electronic 4WD mode switch, the Generic Electronic module (GEM) detects the operations and energized the internal electromagnetic multi-disc clutch to lock the transfer case

Borg-Warner 4406 Specs

Application: Ford F Series
Configuration: part time
Low-range ratio: 2.64-1
Low range: helical planetary design
Fluid type: Mercon ATF 2-qts.
Weight with fluid: 98.5 lbs.
Shift pattern: 2H-4H-N-4L mechanical,
2H-4H-4L electrical part time
Shift control: mechanical or electrical

Which Fords use the Borq-Warner 4406?

Ford F150 4.2, 4.6, 5.4L Manual Shift w/o Torque on Demand 1996-1998
Ford F150 4.2, 4.6, 5.4L Electric Shift w/o Torque on Demand 1996-1998
Ford F150 4.2, 4.6, 5.4L Electric Shift with Torque on Demand 1997-2003
Ford F150 4.2, 4.6, 5.4L Exc. Heritage Electric Shift w/o Torque on Demand 2004-2008
Ford F150 4.2, 4.6, 5.4L AWD 31 Spline Input, 32 Spline Rear Slip 2006-2008
Ford F250 4.2, 4.6, 5.4L Manual Shift w/o Torque on Demand, Shift on Fly 1996-1998
Ford F250 4.2, 4.6, 5.4L Electric Shift w/o Torque on Demand 1996-2003
Ford F250 4.2, 4.6, 5.4L Electric Shift with Torque on Demand 1997-1998
Ford F250 4.2, 4.6, 5.4L Exc. Heritage Electric Shift w/o Torque on Demand 2004-2008
Ford Expedition 4.2, 4.6, 5.4L Electric Shift with Torque on Demand 1997-1998
Ford Expedition 4.2, 4.6, 5.4L Electric Shift w/o Torque on Demand 1999-2002
Lincoln Navigator 4.2, 4.6, 5.4L Shift with Torque on Demand 1998-2002

When Borg-Warner transfer case shifts on the fly

Shifting to 4WD can be performed at speeds up to 55MPH. However, to shift into or out of 4L the vehicle speed must be reduced to less than 3-MPH with the brake pedal applied and the transmission in NEUTRAL in order to shift between 4H and 4Lo.

With the ESOF feature the GEM module see that a shift has been requested and activates the electromagnetic clutch inside the transfer case. The clutch spins the front driveshaft and front driveline up to speed. At the same time the GEM activates the relay that will power the transfer case shift motor. Once the motor rotates and reaches the desired position, contact plate position sensors signal the GEM module that the shift is complete and the GEM cuts power to the shift relays and motor. Once the transfer case front and rear output shafts are synchronized, a spring loaded lockup collar mechanically engages the main driveshaft hub to the drive sprocket. At that point, the front axle collar is engaged and the electromagnetic clutch is deactivated.

Borg-Warner 4406 input sensors

The brake switch is monitored by the PCM which communicates brake pedal position to the GEM module through the communication network.

To clutch pedal position switch is monitored by the PCM which communicates brake pedal position to the GEM module through the communication network.

The electronic 4WD switch is monitored directly by the GEM module.

The throttle position sensor is monitored by the PCM which communicates brake pedal position to the GEM module through the communication network.

The transmission range selector is monitored by the PCM which communicates brake pedal position to the GEM module through the communication network.

The vehicle speed sensor is monitored by the PCM which communicates brake pedal position to the GEM module through the communication network.

Borg-Warner 4406 output devices

The Transfer case clutch relay is a pulse width modulated signal operated relay that operates internal electromagnetic clutch

The 4WD Motor Relay is commanded by the GEM module to operate the transfer case shift motor between 2WD, 4H and 4L modes.

The 4WD/2WD Vacuum Solenoids are attached to upper right side of engine compartment dash panel. The solenoids alternately route vacuum to the vacuum motors which engage/disengage the center axle disconnect collar in front axle assembly

The Generic Electronic Module (GEM) is mounted on fuse block under left side of dash panel.

Borg Warner 44-06 transfer case

Borg Warner 4406 Trouble Code Definitions

P1806 Transmission 4-Wheel Drive High Indicator Short Circuit to Battery
P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure
P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground
P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure
P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short Circuit to Battery
P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure
P1826 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery
P1828 Transmission Transfer Case Counter Clockwise Shift Relay Coil Circuit Failure
P1830 Transmission Transfer Case Counter Clockwise Shift Relay Coil Short Circuit to Battery
P1832 Transmission Transfer Case Differential Lock-Up Solenoid Circuit
P1834 Transmission Transfer Case Differential Lock-Up Solenoid Short Circuit to Battery
P1838 Transmission Transfer Case Shift Motor Circuit Failure
P1846 Transmission Transfer Case Contact Plate ‘A’ Circuit Failure
P1850 Transmission Transfer Case Contact Plate ‘B’ Circuit Failure
P1854 Transmission Transfer Case Contact Plate ‘C’ Circuit Failure
P1858 Transmission Transfer Case Contact Plate ‘D’ Circuit Failure
P1867 Transmission Transfer Case Contact Plate General Circuit k Failure
P 1876 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Failure
P1877 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Short to Battery
P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit

Test 4WD mode switch

The GEM module detects driver choices by the varying voltage created by the 4WD mode switch. To test the switch, use an ohmmeter. Disconnect the electrical connector from the switch and test for these values:

2H 4100-3700Ω

4H 1050-1150Ω

4L 380-340Ω

See these Borg Warner service bulletins

Transfer case shifts on its own

Test transfer case shift relay outputs

borg warner 44-06 transfer case

Contact Plate Sensor Position Codes

Ford transfer case won't shift

Contact Plate Position Sensor Codes

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat

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