What is the Transfer Case? Functions And Types Of Transfer Case.


transfer case may be a part of the drivetrain of four-wheel-drive, all-wheel-drive, and different multiple supercharged shaft vehicles. The transfer case transfers power from the transmission to the front and rear axles by suggests that of drive shafts. It additionally synchronizes the distinction between the rotation of the front and rear wheels and will contain one or additional sets of low vary gears for cross-country use.

The transfer case is essentially a two-speed transmission located at the rear of the standard transmission which provides a low and direct gear, as in jeep. It also provides a medium of connecting the power to the front axle. The shifting mechanism is located on the transfer case. On the hard surfaces and level roads, disengage the front-wheel-drive placing transfer case shift lever in forwarding position. The shorter shift lever controls the gear ratio-low and high. Low gear can only be engaged when the longer shift lever is in the engaged position for a front-drive.

Transfer Case
Transfer Case

Functions Of Transfer Case:

The transfer case receives power from the transmission and sends it to each the front and rear axles. this will be finished gears, hydraulics, or chain drive. On some vehicles, like four-wheel-drive trucks or vehicles meant for cross-country use, this feature is controlled by the driving force. the driving force will place the transfer case into either “two-wheel-drive” or “four-wheel-drive” mode.

This is often generally accomplished by means that of a shifter, just like that in a very manual transmission. On some vehicles, this could be electronically operated by a switch instead. Some vehicles, like all-wheel-drive sports cars, have transfer cases that don’t seem to be selectable. Such a transfer case is for good “locked” into the all-wheel-drive model.
Transfer cases that are designed to permit for traditional road use synchronize the distinction between the rotation of the front and rear wheels, in an abundant identical manner the differential acts on a given shaft. this is often necessary as a result of the front and rear tires ne’er flip at an identical speed.

Completely different rates of tire rotation are usually because of different tire diameters (since front and rear tires inevitably wear at different rates) and different gear quantitative relations within the front and rear differentials since makers can usually have a rather lower ratio within the front vs. the rear to assist with management (such as a three.55:1 within the rear differential and a three.54:1 within the front differential). If the transfer case didn’t conjure the distinction between the 2 totally different rates of rotation, binding would occur and also the transfer case might become broken. this is often additionally why a transfer case that’s not designed for on-road use can cause issues with driveline windup if driven on dry pavement.

np205 transfer case
np205 transfer case

Transfer cases designed for cross-country use will automatically lock the front and rear axles once needed (e.g. once one among the axles is on slippery surfaces or stuck in the mud, whereas the opposite has higher traction). this is often the love the differential lock.
The transfer case could contain one or additional sets of low vary gears for cross-country use. Low vary gears are engaged with a shifter or electronic switch. On several transfer cases, this shifter is the same because the one that selects a 2WD or 4WD operation. Low vary gears permit the vehicle to drive at abundant slower speeds whereas still in operation at intervals the usable power band/rev vary of the engine. This addition will increase the torsion out there at the axles. Low-range gears are used for terribly inclement road conditions, towing an important load, driving on unimproved roads, and extreme cross-country maneuvers like rock crawling. This feature is usually absent on all-wheel-drive cars. Some terribly massive vehicles, like serious instrumentation or military trucks, could have quite one low-range gear.

Types Of Transfer Case:

Transfer cases used on “part-time” four-wheel-drive cross-country vehicles like trucks, truggies, rock-crawling vehicles, and a few military vehicles usually permit the driving force to pick out 2WD or 4WD, moreover as high or first ranges. Those utilized in sports cars and performance sedans are typically “transparent” to the driver; there’s no shifter or choose lever.

Chain drive
Transfer case Chain

Transfer case shift kind


The “Manual Shift On the Fly transfer case” have its selector lever on the driver’s cabin area transmission hub and will even have either 2 sealed automatic front shaft locking hubs or  manual front axle hub selectors for “UNLOCK” and “LOCK” or “FREE”. to interact with the four-wheel-drive system the vehicle should be moving at an occasional speed, the speed at that 4×4 may be engaged depends on the vehicle. this can be just for the four-wheel-drive high setting. to interact with the four-wheel-drive low setting, the vehicle should be stopped and therefore the transmission should be shifted to neutral, then the four-wheel-drive low may be hand-picked.


Electronic Shift On-the-Fly (ESOF) transfer cases have a dash-mounted selector or buttons with a front sealed automatic locking shaft hubs or drive flanges. in contrast to the manual transfer case, this technique includes a transfer case motor. to interact the four-wheel-drive system the vehicle should be moving at a slower speed, the speed at that 4×4 may be engaged depends on the vehicle. this can be just for the four-wheel-drive high setting. to interact with the four-wheel-drive low setting, the vehicle should be stopped and therefore the transmission should be shifted to neutral, then the four-wheel-drive low may be hand-picked.

np205 Transfer Case

When operating vehicles in the 4-wheel drive, more particularly in the low range, an unusually high noise is likely to be encountered in some vehicles. This noise may also be more pronounced at certain road speeds. This is due to the inherent resonance characteristics of the spur gear train used in the transfer case. This noise is neither harmful in any way nor will it affect the overall service life of the assembly. Whenever this noise in transmission and transfer case assemblies is encountered, it should not cause any alarm.

Maintenance Tips or Suggestions of the Transfer Case

The transfer case should be checked every and each time you’re changing its oil therefore because it will have enough lubricant. it’s additionally nice to require a glance at the owner’s manual for your automotive therefore on verify your transfer case’s maintenance interval.   Most of the transfer cases want periodic changes of fluid or oil to take care of high performance and practicality. One should use the stuff or fluid that’s fixed by the manufacturer. However, transfer cases area unit chiefly trouble-free; therefore, they will develop problems over time.

Some of the common problems include: issue in the switch to numerous modes, four-wheel-drive is just operative in some modes or luck of four-wheel-drive operation.   These problems don’t necessarily mean that the transfer case is totally broken. the matter is also at the engagement controls of the transfer case since numerous cars these days use a vacuum or electronic controls to perform the driver’s commands.   In the case wherever your truck is showing some signs of the transfer case problems, have your car’s system checked and analyzed by a {professional|a certified} service professional.  

Transfer Case
Transfer Case

Why Is Transfer Case Fluid Important?

Transfer case fluid will either be traditional or artificial gear oil. However, like several cars, some vehicles need explicit kinds of transfer case fluids. The fluid gets obviate the warmth further as lubricates the inner areas of the transfer case, maintaining its gear turning swimmingly and cool.   After your time, the transfer case fluid gets contaminated as a result of the carbon build-up that results from the cooling of the new drivetrain elements. This could end in poor car’s performance, and therefore the car might shudder once turning further as emitting whining sounds.  

If the fluid becomes contaminated or runs low, it may end up within the failure of the differential. to urge obviate this issue, it’s recommended that transfer case fluid is commonly replaced, usually each thirty thousand miles, particularly in trucks that use or tow four-wheeled drive usually.   When your automotive is in four-wheeled drive or is employed for towing oft, the transfer case fluid usually cycled within the system. This method desires tons of torque; therefore, it needs a lot of heat to transfer.  

Transfer Case Shift Encoder Motor
Transfer Case Shift Encoder Motor

Hence, whereas it’s going to be therefore tempting to attend till 30,000 miles or a lot of to change your transfer case’s fluid, waiting may mean a lowest economical use of the truck’s drivetrain system. Having the transfer case replaced usually can minimize the probabilities of any driveability connected issues. The transfer case fluid modification is often done quicker, and for fewer funds than a differential replacement.

Watch the video below for Explained information about Transfer Case:

Explained information about Transfer Case


transfer case will do a lot of to your four by four truck relating to performance and practicality. However, for your automotive to perform properly, you’ve got to make sure that your transfer case is well maintained to be often dynamical the transfer case fluid to perform well. Why wait? perpetually replace your transfer case’s fluid to avoid a number of the vehicle’s issues.

Watch the video below for Explained animation view of AWD Transfer Case:

Explained Animation View Of AWD Transfer Case

Also, Read These Posts

  • What are All Wheel Drive(AWD) and Four Wheel Drive(4WD) cars?


Creative Blogger And Automobile Engineer.

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