Getting your 4WD stuck in auto in 4Hi or 4Lo can be very unnerving. Here’s what you can do if your GMC Yukon stuck in auto.
When you are driving a heavy vehicle, it is important to know how the delicate parts of the vehicle are working inside.
From the check engine light to traction control, the machinery needs to be in place to work on the road. However, in the case of automatic transmissions, the car can get stuck in certain modes.
One of the main system faults is caused by a problem in the transfer control module. Luckily, this can be replaced and managed when the problem shows up.
Here is a brief outline of what you should do if your truck has run into a problem of getting stuck frequently.
Reset The Battery
What do you do when any kind of technology is failing you? Yes, reboot it. Allow the engine to reboot by unplugging the battery cable for roughly 30 minutes. This might start off the process of shifting from auto to manual.
If this simple step does not work, there might be a bigger issue. Follow the steps in the next section.
Remove and Replace the Transfer Case Control Module
What is it?
A transfer case in a car is a device that enables power transfer from the engine to the wheels. This is located between the differential and transmission, using gears to transfer the power to the front and rear axles.
It is a specialized component used on all-wheel drive vehicles, and for four-wheel-drive vehicles, it is responsible for transferring power to all of the wheels. So, the transfer case splits up the power from the engine to all the wheels, ensuring that your car is moving with equal force.
How does a bad TCCM affect a car?
A failure of the transfer case can result in a number of problems for your car. In fact, there are different reasons why the device can fail, damaging the vehicle.
If not lubricated properly, the transfer case can easily overheat and seize to function. This directly affects the engine, gearbox, and differential.
If the chain between the input and output shaft breaks, there is a possibility of damage to both shafts and the gears in the transfer case.
A damaged transfer case prevents the car from changing gears, directly causing damage to the engine and transmission.
Steps to Replace the Transfer Case Control Module
If the transfer case control module (TCCM) fails, the best idea is to replace it. While there are qualified professionals who can make the necessary changes, you can also try to make the replacement.
Here are the steps you need to follow:
- Preparation: Park your vehicle on an even surface, setting it on the parking brake. To avoid any electrical issues, disconnect the negative battery cable.
- Locate the TCCM: The TCCM will be located near the transfer case of the car. Once you have located the transfer case, find the module that needs to be changed.
- Disconnect the wiring harness: You will find a number of wires and cables connecting the module to the car. Disconnect these wires so that you can remove the module safely.
- Remove the old module: Use a screwdriver, preferably a specialized Philips head screwdriver, to remove the screws that are holding the module. To disconnect the electrical connector, use a flathead screwdriver. To finally remove the module, you will need to remove the bolts with a ratchet.
- Install the new module: Take the new module and place it carefully on the empty spot. Secure it with the necessary bolts and screws. Reconnect all the wiring, making sure that the connections are secure. You need to torque the bolts according to the specifics and reconnect the electrical connector.
- Test the new module: Once you have made the replacement, you have to make sure that the installation is correct. Start up the engine and check if all gears are working in order.
- Finish up: If everything is in order, reconnect the negative battery cable and all the loose wires.
If there is any additional problem after making the replacement, it might be time to get the vehicle checked out by certified mechanics. Otherwise, you are all set to drive away!
Frequently Asked Questions
How do you diagnose a transfer case?
The simplest way to diagnose a transfer case is to turn on the ignition of your car and check the control knob. A healthy transfer shift control indicator should show a flash. In case there is no flash, check the ignition voltage and system circuits to find out which one is at fault.
How do I get my 4WD unstuck?
It is common for a 4WD to get stuck when you are driving a truck in reverse. If this happens, take a moment before shifting into neutral or four-high.
Reverse the vehicle around 60 feet and shift to neutral and then 2WD. This usually disengages the wheel drive and can help run your vehicle again.
How do you manually put a transfer case in neutral?
To manually put the transfer case in neutral in cars like Yukon XL or Yukon Denali, there are 4×4 and 2×4 buttons available that have to be pushed in combination to change it to neutral. There is also an ‘N’ written between the buttons that can help shift the transfer case to neutral.
What would cause 4WD to not engage?
There are multiple reasons that can cause a 4WD to disengage. In most cases, it is an electrical fault from a corroded wire, a faulty dial switch, or the transfer case control module that is damaged in some way.
If your car is running into problems with neutral and auto mode, it is likely that something is going wrong on the inside. To avoid any long-term damage, the best idea is to consult a mechanic at the earliest.
Thank you for reading!