Ford Ranger 4x4s have been popular with truck owners since they were first introduced by the Ford Motor Co. in the mid-1960s. Problems with Ford Rangers can arise with either the low or high 4X4 system or the automatic or manual hubs. If you are having problems with your 4X4, follow these steps to diagnose the trouble.
Understanding how a machine works--whether a car, toaster or computer--is crucial to obtaining a clear understanding of what the trouble spots might be and knowing how to identify them. The Internet is the fastest, most up to date, and cheapest way to get a quick refresher course (or even learn for the first time) how your car works. The animated How Cars Work feature at Cars.com is excellent; it allows you to separately look at each system of the car, from the brakes to the engine to the drivetrain, and briefly explains each animated sequence. Before you begin searching for the cause of your Ford Ranger troubles, make sure you look at this or a similar site first to brush up on your car knowledge.
Next, recruit a friend, spouse or other helping hand and head out to the car to begin diagnosing the problem. Determine if the 4X4 system can be shifted to 4X4 high by pressing the 4X4 button. The dash and 4X4 buttons should light up. If they do not, one of the following is faulty: the dash button, the 4X4 module or the shift motor.
To determine which of these three is malfunctioning, have your friend sit near the module. Press the 4X4 button and ask your friend to listen for the sound of the relays in the 4X4 module. If the relays can be heard, the problem with the 4X4 lies in the 4X4 module computer or the shift motor. The most common problem in this case is a broken stop bumper in the shift motor. If your friend is unable to hear the relays within the 4X4 module, you will need to make sure the 4X4 module is functioning properly.
To check the 4X4 module, unplug the two connectors that are plugged into the left side of the module. Turn the car on and push the reset/test button located on the module. After pushing the button, the LED light located on the module should flash rapidly four or five times. If the LED lights do not flash or flash without stopping, the module is damaged. If the LED lights flashed, then stopped after four or five times, the module is functioning properly and you will need to check other parts such as the shift motor, magnetic clutch, wiring harness and 4X4 switch to determine the cause of the problem.
If your 4X4 is making a grating or clicking noise from beneath the front wheels, the hubs need to be checked to make sure they are locking properly. To test this on a car with automatic hubs, rotate the front axle shafts under the truck. If, after a few turns, the axle locks up and can no longer be turned, the automatic hub is working properly. If, however, the axle does not lock up and you are able to continue rotating it, the hub is either bad or in need of a good cleaning.
To test a car with manual hubs, make sure the 4X4 is off and rotate the axle until it locks up. Again, if the axle does not lock up, the hub is not working or in need of a cleaning.
To determine if the automatic hub is no longer working, take the car out of 4X4 mode and rotate the axle shaft. If the axle does not lock up after a number of revolutions, the hub is most likely not working at all. Repeat this with the other axle shaft. On a car with manual hubs, disengage 4X4, lock in the hubs, and attempt to rotate the axle shafts. If they can be rotated at all, the hub is not working. Repeat this with the other axle shaft.