Hi:

For a 2003 Explorer XLT.

Couple of questions hoping someone can help with.

The owners manual sucks at explaining what the 3 buttons for the 4x4 drive does. The auto 4W is kind-of obvious but the other two are not really explained in the manual and the salesman was clueless. What exactly do I get in high and low modes in terms of what the drive is doing with the power to the wheels?

Does anyone have a link to decoding the axle code. Mine says "45" on the door, I expect this is the 3.55 ratio and no limited slip but I cannot find a listing.

Thanks in advance for any help provided.

 

45 — 3.55 non-limited slip
46 — 3.73 non-limited slip
D4 — 3.73 limited slip


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Principles of Operation

Electric Shift Motor

The externally mounted transfer case shift motor, located at the rear of the transfer case, turns the shift cam assembly. As the shift cam assembly turns, it positions the reduction shift fork for desired transfer case operation. An integral position sensor in the shift motor provides shift motor position information to the 4WD control module.

Mode Select Switch (MSS)

The push button MSS, mounted on the instrument panel, allows the operator to select the 4x4 Auto, 4x4 High, and 4x4 Low transfer case operating modes. The indicator light, on the instrument cluster push button, will illuminate only when the 4x4 Low position is engaged.

Brake Pedal Position (BPP) Switch

The BPP switch is located on the brake pedal. The switch signals the 4WD control module when the operator activates the brake pedal.

Digital Transmission Range (TR) Sensor

The digital TR sensor is located on the outside of the transmission near the transmission shift cable attachment. The digital TR sensor completes the start circuit in PARK and NEUTRAL, the back-up lamp circuit in REVERSE and the neutral sense circuit (4WD) in NEUTRAL. The digital TR sensor also sends a digital output signal to the PCM indicating the manual lever position.

Throttle Position (TP) Sensor

The TP sensor is located on the throttle body. The sensor provides throttle position information to the powertrain control module (PCM). The PCM converts the throttle position signal to a pulse width modulated (PWM) signal, and sends it to the 4WD control module to control and adjust the transfer case clutch duty cycle.

Front and Rear Output Shaft Speed (OSS) Sensors

The externally mounted OSS sensors are located at the rear of the transfer case. The sensors provide the 4WD control module with front and rear driveshaft speeds to control and adjust the transfer case clutch duty cycle.

On vehicles equipped with stability assist, the OSS sensors are present, but not used. The front and rear drive shaft speeds are transmitted to the 4WD control module from the stability assist module. The stability assist module receives the necessary signal from the wheel speed sensors.

Vehicle Speed Sensor (VSS)

The Anti-Lock Brake System (ABS) provides the 4WD control module with the vehicle speed information to control and adjust the transfer case clutch duty cycle.

4WD Control Module

The 4WD control module, located behind the glove compartment, controls the operation of the transfer case in response to the inputs from the shift motor, MSS, BPP switch, digital TR sensor, throttle position output from the PCM, front and rear OSS (on non-stability assist vehicles), stability assist module (if equipped) and the VSS.

Mechanical Operation

The Borg-Warner 44-11 transfer case is available in the Explorer (A4WD) vehicle. The transfer case transfers power from the transmission to the rear axle, and also the front axle when electronically activated.

In 4X4 Auto mode, torque from the transmission is transferred to the input shaft. The input shaft output drives the rear output shaft which, in turn, drives the rear axle assembly. The electromechanical ball ramp clutch assembly drives the drive sprocket after the 4WD control module activates the clutch coil. The drive sprocket turns the drive chain and rotates the front output shaft and the front driveshaft. In the 4x4 High mode, the operation is the same as in the 4X4 Auto mode, except that the 4WD control module consistently activates the electromechanical ball ramp clutch assembly.

The high-low shift occurs when the reduction shift fork moves the high-low collar to lock the planetary gear set to the output shaft. The torque then transmitted through the sun gear from the input shaft turns the front planetary gear set assembly. The front planetary gear set assembly, which is now engaged, provides transfer case speed reduction.

Control-Track® Function

The Control-Track® transfer case uses an electromechanical clutch assembly to control the torque to the front wheels. In Auto mode, while at rest and under cruising conditions, the 4WD control module activates the transfer case clutch at a minimum level. This allows for the slight difference between the front and rear driveshafts which occurs normally when negotiating a corner on dry pavement. Under any of the following conditions, the 4WD control module will increase the torque sent through the clutch to the front wheels in order to prevent or control slip.

Slip is detected by monitoring the front and rear OSS sensors in the transfer case or when slip is indicated by the stability assist module.

Range Function

NOTE: At zero throttle, the duty cycle remains low.

In the 4x4 Low range, with throttle input, the transfer case electromechanical clutch looks at the front and rear driveshafts for maximum 4x4 traction. The transfer case shift motor rotates the shift cam to move the reduction shift fork to the 4x4 Low range position. This low range shift, accomplished through a planetary gear set, changes the torque to the drive shaft from 1:1 to 2.48:1 ratio.

In the 4x4 High range, with throttle input, the 4WD control module signals the transfer case electromechanical clutch to lock the front and rear driveshafts for maximum four wheel drive traction. Never use the 4x4 High range or the 4x4 Low range when driving on dry or merely wet pavement. Use 4x4 High range or the 4x4 Low range only for driving off-road or in severe winter weather.

 

Awesomely helpful reply, thanks.

 

Welcome...

Kind'a a book, but some 'good' read'n...

 

please help! i was wondering if my 1992 ford explorer xlt 4wd gear ratio is also 3.73 limited slip, since D4 is the code under axle on the door. I called ford and they couldn't tell me with my
VIN.they also told me that giving them the axle code D4 wouldn't help. Now i'm lost! Thanks in advance!

 

Axel Codes ...

41 - 3.27 non-limited slip (Explorer/Mountaineer)
45 - 3.55 non-limited slip (Explorer/Mountaineer)
46 - 3.73 non-limited slip (Explorer/Mountaineer)
42 - 4.10 non-limited slip (Explorer/Mountaineer)
D1 - 3.27 limited slip (Explorer/Mountaineer)
D4 - 3.73 limited slip (Explorer/Mountaineer)
D2 - 4.10 limited slip (Explorer/Mountaineer)

Look at the rear diff and see if the axle tag is still there.. A D4 would say 3L73... 'L' meaning limited slip..

 

Right along these same lines, I have a 2000 F-150 with the code under the word AXLE being 27...I am assuming non-limited slip....but what is the ratio?

 

Welcome to the site..

27 3.31, non-limited slip