Transfer case
TRANSFER CASE
Shortened form of "Transfer Gearcase"
A Transfer Case is a part of four wheel drive (4x4 and most all-wheel-drive awd vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of driveshafts.
Functions
1. The transfer case recives power from the transmission and sends it to both the front and rear axles. This is usually done with a set of gears, though some transfer cases are chain-driven. On some vehicles, such as 4x4 trucks or vehicles intended for off-road use, this feature is controlled by the driver. The driver can put the transfer case into either "two wheel drive" or "four wheel drive" mode. This is sometimes accomplished by means of a shifter, similar to that in a manual transmission. On some vehicles this may be electronically operated by a switch instead. Some vehicles, such as all-wheel-drive sports cars, have transfer cases that are not selectable. Such a transfer case is "locked" into 4wd (awd) mode 100% of the time.
2. The transfer case may contain 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 as described above. 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 rockcrawling, or when pulling a heavy load. Again, on all-wheel-drive sports cars this feature is often absent. Some very large vehicles, such as heavy equipment or military trucks, have more than one low-range gear.
Types of Transfer Cases
Those used on off-road vehicles such as trucks,
