It would be good to understand first what a 4-wheel drive in a Chevy truck is so that it will be easy for Chevy 4WD troubleshooting.
A 4 wheel drive or 4X4 or shortly known as 4wd is a driving option in trucks to drive off roads, in snow conditions, rainy weather conditions, and driving the truck in unfavorable situations on land.
By activating the 4 wheel drive option by turning a knob or pressing a switch as per the design of the truck, it provides the power generated by the engine to all four wheels by increasing the traction through a gearbox.
But we should keep in mind an important fact that on normal roads, it’s always advised to run the truck in a 2 wheel drive option.
By opting for the 2-wheel drive option, the wear and tear of the parts that deal with 4-wheel drive can be minimized.
When 2-wheel drive has opted, the power generated by the engine only applies to the axle and wheels in the back of the truck.
This is done because in a normal road condition, traction is not much required, and it allows for lesser fuel consumption and of course minimizing wear and tear of the wheels.
In general, the 4 wheel drive option consumes more power than 2 wheel drive option, as the 4 wheel drive option is used in muddy, slippery roads and to maintain the truck intact on the road.
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DIY Guide: Chevy 4WD Troubleshooting
Common Problem Symptoms of Chevy 4WD
- Excessive Fuel Consumption [4WD Won’t Disengage]
- Lack of Power [4WD Won’t Disengage]
- Heavy wearing of Front Tires [4WD Won’t Disengage]
- Service 4WD Light “ON”
- Rattling Noise [4WD Engaged]
- Less Traction In Mud/Snow
- Indicator Light “ON” [Service 4WD]
- Can’t Disengage 4WD [4WD Light “ON”]
How do you diagnose a 4 wheel drive problem?
Most of the time the driver may come across a situation that after selecting the 4 wheel drive option and if there is any problem in getting engaged, then a light showing “Service 4wd” will glow or an indicator light may twinkle so that we could know that there is a problem in 4 wheel drive.
The driver could hear a significant noise when 4wd is applied, which is also an indicator that there is a problem with the 4 wheel drive.
Another DIY troubleshooting for Chevy 4WD method to confirm that there is a problem in the 4 wheel drive is, on a dry surface, drive your truck and make a turn, if 4 wheel drive is correctly engaged.
Besides , the wheels should not turn easily as the power is distributed to the wheels will not be equal, but if you feel easy to turn it’s concluded that there is a problem in the 4 wheel drive.
To diagnose the problem, a mechanic can be called to check with the computer system in the truck, to check the status of the transfer case data which is responsible for the transformation from 2 wheel drive to 4 wheel drive.
For this purpose, the mechanic could use a scanning tool to detect the problem with a display, whereby it will be shown against the “encoder gear position” as “4wd” when it is correctly engaged else as “2wd”.
This is the advantage of the computerized 4-wheel drive system that one could easily diagnose simply by seeing the display on the scanning tool and can confirm a 4-wheel drive problem.
Common Problems of Chevy 4-wheel drive & Solution:
There are some common problems that every chevy 4 wheel driver experiences. Some of them are due to non-usage for some time and some of them are due to faulty parts and so on.
Let’s see one by one. To indicate any problem a “Service 4 wd” light flashes on the dashboard.
If on the dashboard “Service 4wd” flashes, we should not take it as it recommends for general service, but it is an indication that there is some problem with the 4-wheel drive.
The problem may be due to any faulty switch that is used to select the 4wd option or if wires connecting the 4wd switch and the “Differential” – box which is responsible for power distribution and sliding the shaft to connect with the front axle are worn out.
There may also be some problems in the actuator or the transfer case module.
There might be some leakage or contamination of lubricants. The solutions to these common problems are discussed below.
Chevy 4-wheel drive Actuator Bypass:
Some people may feel bad when there is often a problem with the actuator and the cost that is incurred. To bypass the actuator, several methods are used:
METHOD-1: Firstly, the actuator either can be an old thermal model one of the new models, a piece of PVC, or a metal pipe with a diameter and length which would suit the size of the projection that will come out when the actuator is activated.
Take that pipe separately and put that piece of pipe into the place actually where the actuator is fixed. Now place the actuator.
What happens is the pipe that we put in goes in and presses the fork in there and it becomes a permanent 4-wheel drive when in that option.
In this way, we can bypass Chevy 4 wheel drive. But when you select the 2 wheel drive option, automatically the power won’t go to the front axle so it would be a 2wd.
METHOD-2: Another method to bypass the 4wd actuator is by using products like Posi lock 400 available in the market which has a pull-type cable, when it is attached, it acts as an eliminator of the actuator. But one must look into it, as it is not from Chevy.
Transfer Case Control Module not working:
Another common problem of chevy 4wd that makes the truck glow “Service 4 wd” is the malfunctioning of the Transfer case control module (TCCM).
In the words of a normal man, this is the component that allows the truck to shift from 2 wd to 4 wd or vice versa by considering the speed of the truck which is moving, and decides whether to engage the shift or not.
This is designed for safety purposes. If there persists any problem in this component, many issues one may encounter. There may be difficulty in changing the gears.
The truck may not continue to be in 4wd and it’s one of the major outcomes of a defective Transfer case control Module.
At times one can notice leakage of oil beneath the truck, this may be from a faulty TCCM. By verifying the bottom of the vehicle, by placing it on a jack, one could find where the leakage is.
Unusual noise from the truck, especially when you increase the speed, is an indicator that there is some problem with the TCCM.
One thing that must be noted is even if there is a problem in the transmission, it will also look like a problem in the TCCM, so before confirming, one should not try to fix the problem with a wrong diagnosis.
TCCM is an electrical product that contains several small parts put together in it.
So, it is always better to check with the mechanic to do any work with the parts, to avoid any major problem arising due to ignorance.
Chevy 4WD Switch Problems:
The switches in the Chevy Silverado which is used to get the 4wd mode may have an issue with the soldering done.
If the soldering is gone, resoldering the connections can resolve the problem.
Sometimes there may be a problem with the bulbs, in that case, that can be changed or the fuse might have gone.
In some instances, it may happen that once 4 wd is engaged but it cannot be disengaged due to a problem in the switch. It’s always better to give a check to the mechanic.
Silverado 4WD Switch No Lights:
There is a chance of getting this problem. If the 4wd switch is not glowing even after the ignition is on, keep the truck ON and try to find the #8 fuse box which is beneath the hood, and disconnect it.
Be patient for at least 30 seconds and fix it back in the original position. Try again, to turn on your 4wd switch, it may work this time.
If not, there may be some other problem. Before calling a mechanic, you can check with the ground wire which is fixed outside the driver-side door.
Sometimes rust or mud in the wire connection may also be a cause for such malfunction.
No Power to 4WD Actuator:
A 4 wheel drive actuator is a component that takes the action when we switch on the 4wd option.
The actuator which is like a plug comes out and presses the fork which slides and allows the differential to enable the 4 wheel drive to get activated and then all the 4 wheels get power to move.
The electric component has a power adapter of 12w volt with 5 metal pins or projections which we usually see in most of the electrical plugs.
If there is no power to the actuator, it can be checked with a multimeter to confirm the power input.
If the power input is ok, as per the multimeter, it shows that the actuator is not working. In that case, we have to replace the actuator with a new one.
How much does it cost to fix 4WD?
Chevy Silverado 4WD troubleshooting is based on the model and the prevailing problem in the truck decides the cost that would incur to fix 4wd.
If there is a minor problem like the 4wd switch to be changed, we can replace it and the price of the switch ranges from $16 to $132.
The cost of a 4wd front axle actuator range from about $50 to $135, The transfer case shift may cause $500 to $780.
Likewise, every part has a different price. Depending upon one or more parts to be changed, the cost will change.
We should also take into account the cost of labor to fix it and taxes on the purchase of the parts. Generally, yearly maintenance costs may vary between $700 – $750.
Common Questions About 4WD Troubleshooting
Is there a chance that, even when the 4wd switch is on, the 4wd does not work?
Answer: Yes, if there is a problem in the axle or the transfer case, the truck’s 4-wheel drive indicator may be glowing, without actual 4wd engagement.
How to tell if your 4wd switch is bad?
Answer: Well, it’s very tricky. Most of the time first when you turn on your car and the switch may not turn on, but if you try a few times, on and off, again and again, it may get on.
You can check with the front wheels whether they are rotating. If the switch is bad, mostly you would have a flash on the dashboard showing the “service 4wd” indicator.
Is it good to opt for 4wd while driving?
Answer: The modern automatic 4wd enabled trucks can opt for 4wd while driving, but the manual model 4wd should be changed when the vehicle is in neutral or stopped.
However, while attempting to shift from 2wd to 4wd while driving, make sure that the vehicle speed is within 40mph to 50mph.
Further, it is advised that while using the option ‘4high’ one can shift to 4wd during running and while using the option ‘4low’ it should opt only when the vehicle is in neutral.
Most importantly, irrespective of all the aforesaid conditions 4wd should not be opted for on a normal well-paved road.
Do 4wd need more maintenance?
Answer: Yes, it is obvious that in 4 wheel drive the engine must give power to all four wheels, so the engine must work more, the depreciation of the wheels will be more as the 4WD is designed to travel in the off-road conditions.
It has some special parts which are more prone to get damaged due to the unfavorable conditions and the climate in which the truck is used. So, when compared to 2wd, more maintenance is required for 4wd.
A 4 wheel drive is a sophistication that one can avail in a Chevy to have a better off-road experience. Many times the 4wd option may not be used for a considerable time.
So for better performance, one should operate the 4wd system periodically as per the instructions given in the user’s manual.
Always confirm the working condition of the 4wd before and after an off-road trip. It would help to avoid getting stuck in bad conditions and helps you with Chevy 4WD troubleshooting.