The great American outdoors is a great place to test the limits of your vehicle's four wheel drive (4WD) system. Nothing grips rocky or even muddy surfaces like a 4WD system-equipped vehicle.Sadly, all the fun and adventure may end abruptly if the 4WD actuator fails. Basically, it's the part that switches your vehicle into 4WD mode. It's electronically run, so failure may occur sooner or later.Fortunately, replacing the actuator is a pretty simple do-it-yourself process. All you have to do is find a replacement 4WD actuator, and then it's all just nuts and bolts. Make sure you connect the wires correctly and properly. Faulty or incorrect wiring is the most common cause of actuator failure. Moisture and corrosion can be a factor as well.If you often use your car to navigate deep puddles or small bodies of water, you should check on the actuator regularly. In case you need a replacement actuator, you can browse our catalogs at Carparts.
• Switches your car in and out of 4WD mode
• Guaranteed to help you use your car's 4WD feature more easily
• Comes with the hardware and wiring needed for installation
4WD Actuator Buyer's Guide
- A 4-wheel drive actuator is a device that allows you to automatically switch between two-wheel and four-wheel drive.
- This switch is installed on the front axle tube or on the differential housing.
- Inside the actuator is a shift fork that locks the gears and driveshafts together, allowing the transfer case to split power between the front and rear differentials 50-50.
- Before the time of automatic actuators, drivers had to step out of the vehicle to pull a lever that manually locks the front wheels to the front half-shafts, driveshaft, and differential.
- Today, drivers may switch from two-wheel to four-wheel drive by turning a knob or pressing a button on the dashboard.
- There are three types of 4WD actuators based on the mechanism that activates the fork inside the device. These are vacuum, thermal, and electrically operated 4WD actuators.
- The most common 4WD actuator problems are vacuum leaks, mechanical failure, and electrical failure.
- The cost of a 4WD actuator varies between different makes and models. An OE replacement 4WD actuator can cost as low as $40 for an individual piece. This part is also sold in sets of two priced anywhere between $100 to $400.
What is a 4WD actuator?
A 4-wheel drive actuator is a device that allows you to automatically switch between two-wheel and four-wheel drive. It is usually seen in trucks and SUVs with part-time 4WD systems. Also known as a front axle actuator, this component activates the mechanisms which allow torque to be applied to the front wheels, so they spin at the same speed as the rear wheels when needed.
This switch is installed on the front axle tube or on the differential housing. Inside the actuator is a shift fork that locks the gears and driveshafts together, allowing the transfer case to split power between the front and rear differentials 50-50.
How does a 4WD actuator work?
To understand the purpose of a 4 wheel drive actuator, let’s do a quick review of how a part-time 4WD system works.
When automakers refer to a vehicle that has four-wheel drive, they are usually talking about a part-time 4WD system. Vehicles with a part-time 4WD system may switch between two-wheel-drive or four-wheel-drive as their driving conditions change.
On dry and paved roads, a vehicle with a part-time 4WD system is designed to operate in two-wheel-drive. In this mode, 100% of the torque from the transmission is applied to the rear wheels because the driving conditions provide enough traction to ensure vehicle movement.
The driver must switch to four-wheel-drive to utilize traction from all four wheels while driving in deep snow, over streams, or up muddy hills. This will send power to the front wheels and prevent the rear tires from spinning endlessly while the vehicle remains stuck because of low-traction conditions.
Before the time of automatic actuators, drivers had to step out of the vehicle to pull a lever that manually locks the front wheels to the front half-shafts, driveshaft, and differential. Today, drivers may switch from two-wheel to four-wheel drive by turning a knob or pressing a button on the dashboard.
Modern 4WD systems use a motorized actuator to engage the transfer case. This essentially locks the series of gears and chains that connect the front-axle driveshaft to the front differential, enabling the transfer case to transfer torque to both front and rear wheels. The actuator also sends a signal which activates the 4WD light on the instrument panel on the dashboard.
Types of 4WD actuators
There are three types of 4WD actuators based on the mechanism which activates the fork inside the device. These are vacuum, thermal, and electrically operated 4WD actuators.
This type of 4WD actuator has a diaphragm inside the device which uses vacuum pressure to engage secondary mechanisms.
A thermal actuator is a type of switch that anywhere between a couple of seconds to a minute to warm up and reach its operating temperature. In some cases, the actuator will fail to engage if temperatures are too low or if the front axle is submerged in cold water.
Fully electric 4WD actuators engage the front axle immediately without having to warm up.
Common 4-wheel drive actuator problems
Vacuum hoses connected to the 4WD actuator can become cracked and leak over time. Heat and chemical damage may also cause the material to deteriorate.
The location of the actuator exposes it to extreme heat, road chemicals, and debris which could electrical connections to corrode or fail.
The mechanical components of a 4WD actuator like the shift fork and shift cable may wear out over time. These parts are also prone to sticking, especially if four-wheel-drive has not been activated in the vehicle for a long time.
How to tell if a 4WD actuator is bad
A bad 4WD actuator will prevent your vehicle from switching from two-wheel to four-wheel drive. In most cases, the PCM will detect the problem and log a diagnostic trouble code. When this happens, your vehicle’s Check Engine Light will be illuminated, and you’ll need to connect your vehicle to an OBD-II scan tool to retrieve the trouble code.
The steps and tools needed for the diagnosis and repair of 4WD actuators will also depend on which type is installed on your vehicle. The location of this part also makes it difficult to access for people with limited tools and automotive knowledge. For an accurate diagnosis, it is best to take your vehicle to a trusted auto repair shop and have a licensed mechanic check it for you.
How much does it cost to replace a 4WD actuator?
The cost of a 4WD actuator varies between different makes and models. An OE replacement 4WD actuator can cost as low as $40 for an individual piece. This part is also sold in sets of two priced anywhere between $100 to $400.
Finding the right fit
CarParts.com carries a wide selection of 4WD actuators for all types of vehicles. Our catalog was handpicked by industry professionals who understand the importance of using only high-quality replacement parts. Start your search today by plugging in your vehicle’s correct year, make, and model into our website’s built-in vehicle selector.
What to Consider when Purchasing a 4WD Actuator
When doing long-distance drives, you’ll never know when you’ll pass by rocky or muddy terrains. And if you love to conquer the roads less traveled or you regularly visit a relative in the suburbs, you’d better take good care of your 4WD ride.
If you think its 4WD actuator has seen better days, have it replaced before saying yes to any off-road or long-distance trip. Here are some of the factors to consider before you purchase the replacement actuator that fits your ride well and addresses your needs:
Your new 4WD actuator will not be efficient or may not work at all if it isn’t compatible with your ride and all the components it needs to work hand in hand with. So before shelling out some bucks for a new unit, make sure that it is specifically designed for your vehicle.
When purchasing online, you can ensure part compatibility by getting an actuator that’s made to replace your old actuator’s part number. It’s also wise to read the part description to find out all the specs and features of the part. See to it that all the specs of your new actuator match that of the old. Besides efficiency, getting a compatible unit also ensures easy installation.
There are replacement 4WD actuators that come with gasket and clips but don’t include harness. Some units include pig tail and terminals while others are sold as a kit, which comes complete with wiring harness, gaskets, clips, relay, terminals, mounting brackets, and other hardware you may need to ensure easy installation. You should base your choice on what you need.
If your actuator necessitates replacement due to age and regular wear, chances are all the hardware securing it in place have also worn out along with the actuator, so it would be a good decision to replace them all at once.
It’s always wise to get a product that’s backed by good manufacturer warranty as this is an assurance that the makers have confidence in the quality and performance of their products. The warranty will also get you covered in case you discovered that the 4WD actuator has manufacturing defects after using it for some time.
How to Replace a Bad 4WD Actuator
There’s no better way to enjoy the great American outdoors than to take your ride for a drive and engage its 4WD system. With this feature, you need not worry about going through rocky or muddy terrains because you know you’ll have good grip. But, all the fun and thrill can end up suddenly once your 4WD actuator stops working.
It’s a good thing that replacing this component is fairly easy. You just have to get the right replacement unit and installation will never be a problem even for a novice DIYer like you.
Difficulty level: Easy
What you’ll need:
- Jack stands
- Wheel chocks
- Hydraulic jack
- New 4WD actuator
- Wrench or socket set
Step 1: Prepare the vehicle by parking it in a solid, level ground and engaging the parking brake. Brace the rear tires with wheel chocks to keep the vehicle from rolling.
Step 2: Roll the hydraulic jack underneath the vehicle, positioning it under the car frame. Raise the vehicle’s front. Secure it by placing jack stands under another section of the vehicle’s frame.
Step 3: If the vehicle is outfitted with a front differential carrier shield, you need to remove it using a wrench or socket set.
Step 4: Locate the 4WD actuator. It would be wise to consult your owner’s manual first before starting with the task for you to know the exact location of the part. Once you’ve found it, detach the electrical connector from the actuator.
Step 5: Remove the actuator from where it is installed by turning it counterclockwise.
Step 6: Get your replacement actuator and compare it with the old one. If it’s a perfect match, then apply sealant to the threads of the new actuator. Make sure to use the right sealant. Consult your owner’s manual for your manufacturer’s recommendation.
Step 7: Carefully install the 4WD actuator by inserting it in place of the old one and turning it clockwise. Tighten the actuator to the manufacturer’s specifications, which can be found in the owner’s manual or in the note or label that comes along with your replacement unit.
Step 8: Connect the electrical connector to the new actuator. Reinstall the front differential carrier shield, if your ride is equipped with one, and lower the vehicle.