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The transfer case is one of the more important parts of a 4WD or AWD systems that SUVs and cars are equipped with. It is meant to distribute power to all four wheels for the best grip and performance and is put to good use given our weather conditions. It is a complex piece of machinery and contains within it gears and transfer case fluid to keep things lubricated. And as with any part on the car, it needs periodic inspection and maintenance. So let’s look at what transfer case fluid is and how often it should be changed.
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What is a transfer case?
All-wheel or four-wheel drive really is driving our vehicle marketplace with 60% of autos being equipped with this increasingly popular feature. The methods used by automakers to achieve power to all four wheels vary and knowing whether or not your ride has a separate transfer case is key to keeping up with maintenance to help ensure a long trouble-free drive.
For smaller vehicles, many manufacturers use a device incorporated into the transmission that shares the same fluid meaning following the recommended transmission fluid change intervals automatically takes care of things.
But larger SUVs and trucks often use a separate transfer case; aptly named for its function of transferring power to a second set of wheels. The ‘case’ is mounted directly to the transmission and connects to two separate drive-shafts; one to the rear wheels and one to the front. Inside they contain shafts and gear sets with mechanisms to power both axles on command. They don’t have a cooling system as their function and design don’t develop much lubricant-killing heat that their lubricant can’t handle.
What is transfer case fluid?
As gears and shafts move constantly inside a transfer case when its vehicle is in motion, lubricant is needed to prevent wear and help cool bearings and other moving parts. It’s usually available in traditional and synthetic blends and acts like a cross between axle gear oil and transmission fluid. Most automakers require a specific formula for their transfer case fluid so ensure your service provider or you (for the DIYers) use the correct and manufacturer-accepted type. Most fluids for common and high-volume cases can be sourced from independent parts’ stores as well as dealerships. Prices can range from $20-$100+ per litre, but most cases take less than 2 litres.
Signs your transfer case fluid needs replacement
Failing transfer case fluid seldom provides any warning before component damage occurs. Most cases used today don’t have temperature or fluid level warning systems and even those might not help before shaft bearings and gears break down. Cases can leak showing external signs of problems, but these are not usually the fault of the fluid. Having a visual and fluid check of the case at every oil change is an easy way to stay on top of things. Not all oil change outlets will check transfer case fluid as a rule, because almost all cases don’t have dipsticks and a plug must be removed to verify the fluid level and condition. Ask at the service counter to be sure.
How often should transfer case fluid be changed?
Fluid service intervals vary widely depending on the maker and range from 60,000 km to over 100,000 km; check your owner’s manual or call your dealership to be sure.
Transfer case fluid change cost
The labour portion of this service averages around a half hour at the shop rate ($70-$100 range) and as mentioned above fluid prices range from $20-$100 per litre although some shops will use a competitive menu price.
How to check transfer case fluid
Most cases have a drain and check plug. Unscrewing the check plug will give you access to check condition and level by inserting a short length of stiff wire. If the fluid is black and has a burnt odour, it’s time to change it.
Like most automotive components with moving parts, it’s a use it or lose it proposition. Engaging the four-wheel drive for a short run monthly is a great way to ensure the system will work when you need it. Listen for any unusual or new noises such as grinding or howling. Also any vibration with the case engaged should be a sign to have a pro check things out.
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