How to Test Transfer Case Shift Motor?

The transfer case is an essential system component that plays a significant role in distinguishing four-wheel drive (4WD) and all-wheel drive (AWD) vehicles. Center differential is found on (AWD) while transfer case in four-wheel drive provides superior traction to the truck, thereby giving peak performance in off-road and challenging terrain. This is quite possible because the transfer case has features that allow the driver to choose whether to transmit power to both rear and front wheels.

If the transfer case fails, you will find it difficult in staying in 4WD or unable to switch from 4WD to AWD, and in rear situations, it’ll affect the rear differential since both of them are mechanically connected. Hence, the need to know how to test transfer case shift motor and replace it. So, in this article, we’ll discuss at length the transfer case and how it works and a host of signs and symptoms you may experience when it fails.

What is the transfer case control module?

The transfer case control module (TCCM) controls the general operation of a four-wheel drive. Its operation requires processing, executing and verifying the completion of the system operation. Where is the transfer case control module located, and what does it do? The transfer case control module is located on the driver side dash, on the steering column.

transfer case shift motor

As I have explained, the TCCM oversees the shifting in the 4WD vehicle system operation. So, how does it do that? The TCCM determines the processing, executing, and verifying the movement using the truck’s speed and the transfer case mode. Once the shifting is possible, the TCCM will finish the process by activating the transfer case encoder actuator. It can also switch off the front differential locking motor. And if the shifting is not possible, the selector switch will pop up and blink light for 45 seconds.

What are the symptoms of a bad transfer case motor?

The transfer case is designed to last the vehicle’s lifespan – but that’s not usually the case. Just like any mechanical component, when the transfer case fails, it will leave some symptoms to notify the driver of a problem with the system component. Below are the common signs you’ll notice when the transfer case shift motor fails.

Difficulty staying in four-wheel drive (4WD): One of the common problems you’ll notice when the transfer case fails is difficulty staying in 4WD. However, the issue can result from a host of other problems like the driveshaft or differential issues. It might also be an indicator of an internal transfer case problem.

Four-wheel drive (4WD) not engaging or disengaging: There are many reasons for 4WD to be disengaging or not engaging. The root cause ranges from electrical faults in the control system to defective shift mechanisms. The transfer case may have an internal problem.

Embarrassing Humming, growling, or grinding noise: A common sign of a problem on the vehicle is a strange noise that isn’t present before. Awkward and annoying noise can be bothersome, and it may indicate issues around the corner. If you hear a humming, growling or grinding noise that increases as you accelerates the vehicle while driving down the road, chances are, it’s coming from the transfer case. It could be due to low fluid level or mechanical damages such as damaged gears, loose chains, or bad bearings.

Puddle buildup under the transfer case: The only reason for a greasy or oily formation under the vehicle is a leak around that area. And the oil leak can be coming from the transfer case. Visually inspect if the leak is from the transfer case by sliding under the truck. The transfer case is located at the rear-end of the transaxle or transmission assembly.

Gear shifting issues: Another common symptom of a bad transfer case is gear shifting issues between gear ranges. However, the root cause might be a damaged linkage or low fluid level. When having issues with gear shifting, before assuming you have a problem, ensure you’re following directions in the owner’s booklet for how to operate the transfer case. For instance, before shifting to 4L, you need to stop the truck and place the transmission in neutral. Otherwise, you’ll hear a growling or grinding noise when engaging the gears. This is a common Ford transfer case problems.

Illuminating four-wheel drive warning light: Some vehicles are equipped with ‘4WD service required message’ (or similar message) that will come on the dashboard when there’s an issue in the system. In contrast, other vehicles will blink continuously to indicate a problem within the system.

How do I know if my transfer case control module is bad

The common symptom of a bad TCCM is a warning message or warning light on the dashboard. If the transfer case module fails, there will be no power to transfer case shift motor. Aside from this, there are hosts of other symptoms listed below.

Four-wheel drive (4WD) service message: Most times, it’s normal for this message to pop up on the driver information centre (DIC). Normally, the maintenance or service message should go away when you turn off the engine and start the vehicle again. However, the message could indicate a bad TCCM and/or along with a button pack or encoder motor.

Engine hesitation after taking off: several factors can cause engine hesitation, and the transfer case control module can be one of them. If you’re driving and it hangs back kicking off the engine, it could be an indicator of a transfer case control module. This can happen if TCCM fails and send the wrong signal to the transmission. You need to replace the transfer case control module to fix the engine hesitation.

4×4 system not working: Have you tried engaging the 4×4 system by shifting the switch panel, and it has no effect? Or every single component on the panel isn’t working, and you are wondering if this is a significant repair issue. If this is the case, you need to carry out a transfer case control module self-test to know whether this component needs replacement. Switch on the ignition and observe the transfer case shift control indicators, you should notice a flash.

You also need to diagnose some system circuits if you do not notice any flash. Check for battery and ignition voltage. Check the transfer case shift control switch connector and the ground circuit for earth. If all the circuits are okay and the transfer case control module fails the test, you need to replace it.

Can you drive with a bad transfer case?

Driving with a bad transfer case can lead to series of significant mechanical problems. One of the common problems of the transfer case is a fluid leak. There’s a seal between the transfer case and the transmission, and if that seal goes bad, it will cause an internal or external transmission fluid leak. When this happens, it may empty the transmission fluid and result in catastrophic damages to the transmission. Another common problem and why you shouldn’t drive a vehicle with a lousy transfer case is a faulty encoder motor Which will register a C0327 fault code in the vehicle computer system when it fails and cause engine hesitation and 4×4 performance issues.

How to test transfer case shift motor

The transfer case shift motor is 99% the root cause of the transfer case issues. I’ll be guiding you on Ford ranger transfer case motor testing. However, this guide is valid for any vehicle make and model transfer case testing.  To begin the test, you need some common mechanic tools, such as jack and jack stands (optional) and a test light.

Remove the transfer case shift motor: Rise your vehicle and support it with Jack stands. Slide under and locate the transfer case motor.  It looks like a window motor and it sits on the rear of your transfer case. It usually has 3-4 bolts holding it. Remove the bolts and unplug the wiring connectors. Remove the transfer case motor and place it on a table to carry out the test.

Test the transfer case motor with a test light (Ohm preferably): locate the yellow and orange wire on the actuator because that controls the motor. These two wires go into the motor itself. Set the Ohm to 200 ohms. Then, place the probes on the orange and yellow wires. You should be getting around 2.2 – 2.7. Anything above this range is abnormal and shows you have a fault shift motor.

Test the transfer case motor with a battery back: Another way to test the transfer case motor is by using a car battery or a portable jumper pack. Take your multimeter leads and connect them to your jumper pack terminals. Make sure you don’t cross the probes. The idea of this test is to get the gear to move. Ensure you connect the probes to the orange and yellow wires. The transfer case motor gear should move in both directions, and the movement should be free. (But not too free). If the reverse is the case, you have a lousy shift motor that needs replacement. The transfer case shift motor is estimated to be around $50-$80.

Final Thought

So if you notice any of the symptoms above, you should test and fix the transfer case motor before it leads to more significant problems, such as damages to the transmission or transaxle assembly. That’s why knowing how to test transfer case shift motor is essential and could save you from higher repair cost. However, the first thing you have to do when you notice two or more symptoms above is to run an in-depth diagnosis on the vehicle using a high-end scan tool. The transfer case has a lot of system components with actuators and sensors. Therefore running a scan will save you headache and save money at last.

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Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

One thought on “How to Test Transfer Case Shift Motor?

  1. 2019 Yukon XL Denali –
    What causes the dash display to show the message “slow down to 3 mph to shift to 4 low” when the shift knob is in 2WD and driving down the highway? Even though shift knob is in 2 WD, the shift knob position light for 4 wheel low is blinking.

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