Transfer Case Service

Car maintenance: Transfer Case

Transfer case functions:

The transfer case is a mechanical component in all four-wheel-drive and all-wheel-drive vehicles. It distributes engine power from the transmission to the front and rear drive shafts, acting as a differential between the front and rear wheels. Indeed, the transfer case makes sure you have power available for both the front and rear axles. For example, if you have a rear-wheel drive SUV, power goes to the rear wheels until you need 4-wheel drive. That's when the transfer case steps in and transfers some of the power to the front wheels as well.

The transfer case can be controlled manually or electronically and allows for gear reduction at low or high speeds. You might use a shift lever to go into 4-wheel drive, or it could be a button on the dash or it might even go into 4-wheel drive automatically, depending on your vehicle.

What are the signs indicating a faulty transfer case?

With time and kilometres, the lubricant becomes contaminated, additives lose their properties, and tiny suspended particles can cause premature wear. There isn't a filter in the transfer case, so if the contamination is allowed to stay for too long, it'll further accelerate wear.

There are several things that affect how often you should change the fluid, so tell your certified NAPA AUTOPRO technician how much you use 4-wheel drive, if you drive in wet environments like crossing streams or through mud and snow. That kind of stuff really shortens the drain interval. When needed, your certified NAPA AUTOPRO technician can replace the fluid for you during routine maintenance. 

One of the main signs indicating a faulty transfer case is strange noises coming from your vehicle at certain times. More specifically, you might notice unusual noises at certain speeds or when you shift gears. It may also indicate that you need to add more lubricant in your transfer case.

If you recognize any of those signs, you need to contact your NAPA AUTOPRO technician for a transfer case maintenance.

How often do you need to maintain your transfer case?

The transfer case is serviced by periodically draining its fluid and replacing it with fresh fluid. We also check for leaks and damage. Transfer case fluid cools and lubricates the gears, chains, bearings, shafts and other parts. Depending on the application and the manufacturer’s specifications, the lubricant can be oil of a specific viscosity or automatic transmission fluid. Your certified NAPA AUTOPRO technician knows the right lubricant to use for each vehicle and how often it should be replaced.

Transfer case parts will eventually wear out and you'll have to make repairs. But properly servicing your transfer case will keep that day as far in the future as possible. Your owner's manual may not have a recommended interval for when you should change your transfer case fluid - so ask your service advisor.

Learn more about the transfer case from our NAPA AUTOPRO experts in the video below: