How to Service a 4-Wheel Drive Like an EXPERT
When you Service a 4-wheel drive it’s not like servicing a regular 2WD vehicle since there are more drivetrain and other 4WD components that require inspections and regreasing. 4-wheel drives have transfer cases, drive shafts, and other critical 4WD components that need to be attended to timeously. This article will discuss the various components that are unique to 4-wheel drives and what needs to be included with every service interval.
When you service a 4-wheel drive, it’s crucial to inspect critical drivetrain components like differentials, gearboxes, and transfer case fluids. Additionally, greasing driveshaft components such as yokes, ball joints, and U-joints is essential. Checking brake lines and electronic sensors beneath the vehicle is also vital during service.
The next part of this article will discuss the various components in detail that need to be inspected and serviced on any 4WD vehicle.
Table of Contents
How To Service A 4WD: ALL Components
When servicing a 4-wheel drive the initial phase of the service is just like any other vehicle. This means all vital lubrication, such as engine oil, oil filters, air filters, and fuel filters will be replaced as normal. If you have a petrol 4-wheel drive, you will need to inspect, clean, and if necessary change plugs as well.
Sure, here’s the text rewritten as a list:
- Service a 4-wheel drive:
- Clean and spray electrical components such as:
- Plugs
- Sensors
- Wires with dielectric spray for proper contact and voltage transfer.
- Clean and spray electrical components such as:
- This maintenance is crucial because of challenging off-road conditions like:
- Deepwater submersions
- Dusty roads
- Exposure to ice/snow
- These conditions impact long-term 4WD performance by:
- Quickening the clogging of filters
- Causing early moisture exposure in electrics
- Accelerating drivetrain lubrication loss.
Service a 4wd Drivetrain
Your drivetrain is situated below the vehicle and is the most vulnerable of all the 4-wheel drive components. Most of the drivetrain is exposed which means it takes quite a beating when driving off-road. The 4-wheel drive drivetrain consists of various movable joints and knuckles that need to be thoroughly inspected.
| Vehicle Component | Description |
|---|---|
| Front U-joints | Joints connecting front driveshaft |
| Rear U-joints | Joints connecting rear driveshaft |
| Yoke re-lubrication | Yoke requiring fresh lubrication |
| Differential oil levels | Check/Top-up levels of oil in the differential |
| Transfer case oil levels | Check/Top-up levels of oil in the transfer case |
| Gearbox oil levels | Check/Top-up levels of oil in the gearbox |
| Transfer case actuator | Component responsible for transfer case operation |
All the above-mentioned components are unique to 4-wheel drive vehicles and require special attention before and after every major trip. At least an inspection is necessary.
Service a 4wd Yoke
The yoke, found at the rear driveshaft near the rear differential, enables suspension flexibility without harming the driveshafts. It contains grease for lubrication and protection, allowing articulation without damage. Dusty roads expose the driveshaft to knocks during technical off-road drives. Regular inspection of the 4WD yoke for damage and play is essential, as it might snap if not lubricated. Lack of grease due to water exposure or depletion can lead to metal fatigue, causing potential component failure.
Service a 4wd – Transfer Case Fluid
Inspect this fluid for metal filings during major services. It’s a high-torque component responsible for transferring engine power through the drivetrain to the axles. Check the transmission case oil levels; excessive oil may indicate a seal leak between the transmission box and the transfer case. Urgently address this issue before engaging in 4WD activities to avoid potential damage.
Service a 4WD – Gearbox Fluid
The automatic gearbox is a high-stress part. Regularly check its oil levels and condition for proper lubrication, heat reduction, and signs of wear, including leaks and metal filings, which may signal friction and severe wear.
Service a 4WD – Actuator Switch
The actuator switch is an electrical switch with a shaft that is positioned below the 4-wheel drive on the transfer case. The function of the switch is to engage the 4-wheel drive hi and lo when the dial is selected in the cabin. If you notice the 4wd light flashing when in 2wd then you should inspect and service this component ASAP.
Due to its position under the vehicle, it is also very exposed and vulnerable to the elements off-road. Remove the switch connections, clean, and spray with a dielectric spray.
Service a 4WD – Brake Lines
Most vehicles, including 4WDs, have brake lines beneath the chassis, susceptible to damage. Regularly check for damage, and leaks, and secure attachments to prevent obstacles from dislodging or damaging the lines during off-road driving.
Service a 4WD – Diff-Locker
Diff-lockers, typically rear-mounted, are present in some 4WDs on both rear and front differentials. They serve to unite wheel axles for improved traction on challenging terrains with low grip. Use them only when traction is poor, preventing wheel slippage. Failing to engage the rear locker properly could damage the drivetrain and tires, leading to drivetrain binding. Test and maintain differential lockers by cleaning and using dielectric spray for electrical connections.
Service a 4WD – Diff Fluid
Differential fluids lubricate gears and should be changed every 35,000 miles, following the owner’s manual for the right oil grade. Check and top up oil levels as needed.
For rear diff oils in 4WDs, change every 15,000 to 36,000 miles. Always check the manual for the correct lubricants. Using improper lubricants for lockable differentials may damage them or prevent proper activation.
Service a 4-wheel drive – U-Joints
U-joints are what in most cases allow the 4-wheel drive to flex and articulate. They are a perishable component and should be checked every so often for leaks in the rubber seals and to ensure proper lubrication. Check for dripping rust water or cracked seals which will indicate it’s time to replace.
A loud popping sound is usually associated with a damaged or dry u-joint. You can read more about that here: Loud Popping Sound When in 4WD
Most U-joints have greaseable nipples for adding grease to small housings with metal pins. These vulnerable parts can be damaged off-road, so inspect them before and after trips. A damaged nipple could lead to grease leakage and subsequent component failure.
Reset the 4-Wheel Drive Service Light
For directions on how to reset the service light, check your owner’s manual for the correct steps. Each 4-wheel drive manufacturer has its method of doing this.
Below is a short video demonstrating how to reset a VW Amarok’s service light.
Final Thoughts
Look after your 4-wheel drive and it will look after you. Do the due diligence to inspect the various components listed above since that will give you peace of mind every time you venture into the unknown.
