Transfer Case Repair & Service

Transfer Case Repair, My Transmission ExpertsExpert Mechanics in Houston, Katy, Kingwood & Montgomery TX

You may not know much about transfer cases, but if you have a 4-wheel drive vehicle, you’ve got one. Chances are you won’t think too much about it until you need transfer case repair or service. The transfer case allows you to have power available for both the front and rear axles.

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 transfers some of the power to the front wheels as well. You may use a shift lever to go into 4-wheel drive, it could be a button on the dash, or it may even go into 4-wheel drive automatically, depending on your vehicle.


The transfer case receives power from the transmission and sends it to both the front and rear axles. Although this can be done with a set of gears, the majority of transfer cases today are chain driven and can break down or wear out. Some vehicles, such as four-wheel-drive trucks or vehicles intended for off-road use, are controlled by the driver. They can put the transfer case into either “two-wheel-drive” or “four-wheel-drive” mode. Sometimes accomplished by means of a shifter, it’s similar to that in a manual transmission.

On some vehicles this may be electronically operated by a switch. Some vehicles, such as all-wheel-drive sports cars, have transfer cases that are not selectable. Such a transfer case is permanently “locked” into all-wheel-drive mode.


An on-road transfer case synchronizes the difference between the rotation of the front and rear wheels, in much the same way the differential acts on a given axle. This is necessary because the front and rear tires never turn at the same speed when front and rear tire sizes differ. Off-road use transfer cases are designed to mechanically lock the front and rear axles when needed. This is the equivalent to the differential lock.


The transfer case of Off-road vehicles generally have one or more sets of low range gears. Low range gears are engaged with a shifter or electronic switch. On many transfer cases, this shifter is the same as the one that selects 2WD or 4WD operation. Low range gears slow down the vehicle and increase the torque available at the axles. Low-range gears are used during slow-speed or extreme off road maneuvers, such as rock crawling or when pulling a heavy load. This is often absent on all-wheel-drive cars. Very large vehicles, such as heavy equipment or military trucks, have more than one low-range gear.


To service the transfer case, periodically the draining of its fluid and replacing it with fresh fluid is necessary. It is also necessary to check for leaks and damage. Transfer case fluid cools and lubricates the gears, chains, bearings, shafts and other parts. However, after a period of time the additives in the fluid wear out and it doesn’t protect as well.

Also, bits of metal and clutch material will wear off and contaminate the fluid. There isn’t a filter in the transfer case, so if the contamination is allowed to stay for too long, it’ll further create wear. A burning smell in a vehicle could also indicate the transfer case may be out of fluids.

Your owner’s manual may not have a recommended an interval for when it’s necessary to change your transfer case fluid – so ask My Transmission Experts. There are several things that affect how often the fluid needs to be changed, so tell us 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.


Transfer case parts wear out just like other automobile parts and need replacement or service after a while. However, properly servicing your transfer case will keep that day as far in the future as possible. Call us or contact us online to schedule a transfer case repair estimate in Houston, Katy, or Kingwood today.


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