Transfer Case Parts
A transfer case is a gear box that is connected to the transmission on four-wheel drive and all wheel drive vehicles. It is also sometimes referred to as a "transfer gear case" or "transfer box." The transfer case on four-wheel drive vehicles is what transfers the power to either the front axle or the rear axle by means of two separate drive shafts.
The transfer case on part time four-wheel-drive vehicles usually will allow the driver to choose if he wants to select 2 WD or 4 WD as well as choosing whether they want to use the high gear or low gear ranges. This type of transfer case is mostly used in off-road vehicles like rock crawling vehicles or military vehicles. When a transfer case is used in a sports car there is usually not a shift or selector lever available for the operator to use.
A transfer case is typically attached to the back of the transmission of 4 wheel drive vehicles. Power from the engine is directed through the transmission to the transfer case and then either to the front or rear wheels. If it is at all wheel drive vehicle, then power will be directed from the engine to the transmission, then to the transfer case and then to all four wheels.
Most transfer cases have two different types of internal operations. If it is a gear driven transfer case it will use sets of internal gears to transfer power to both the front and rear driveshaft. A gear driven transfer case is built to be very strong and is usually found in large trucks. However today, some passenger cars are currently being produced that have a gear driven transfer case.
The other type of transfer case is a chain driven transfer case. This type of case predominantly uses a chain to drive the front axle. However it can drive the rear axle as well. People tend to like a chain driven transfer case more than a gear driven transfer case because it is quieter. Chain driven transfer cases are typically used in small or full-size pickups and in SUVs or Jeeps. You will find that a lot of off-road driving enthusiasts like to use gear driven transfer cases so that they will have the strength that they need for rock climbing and such. These enthusiasts gladly put up with the added weight and noise that they get from a gear driven transfer case in order to have the added strength for their outdoor four-wheel-drive competitions and entertainment.
You will find that there are two different classifications for transfer cases. They can be classified as "independent" or "married." If the transfer case is totally separated from the transmission, it is classified as an "independent transfer case." An "independent" transfer case has a short driveshaft that travels between the transmission and the transfer case. "Independent" transfer cases are not as popular as "married" transfer cases. A "married" transfer case is one that is directly bolted to the transmission. Sometimes "married" transfer cases can even be found in the same housing as the transmission. The modern Subaru is one such vehicle that has a transfer case like this. The "married" transfer cases are more popular and used more than the "independent" classification of transfer cases. They are most often found in pickups and SUVs. Whereas, you will find the independent transfer cases most often used in long wheel base vehicles, like military vehicles or commercial trucks.
It is interesting to note that all the time 4 WD vehicles, such as monster trucks, have no transmission at all, but use independent three speed transfer cases. You can find transfer cases for sale and auto parts stores and many online websites.
