Transfer case

A part of the vehicle's drivetrain, it employs drive shafts to mechanically deliver motive power.

The transfer case also synchronizes the difference between the rotation of the front and rear wheels (only high-speed 4wd-Awd systems), and may contain one or more sets of low range gears for off-road use.

Automated versions used in sports cars and performance sedans are usually "transparent" to the driver; there is no shifter or select lever.

These are generally strong, heavy units that are used in large trucks, but there are currently several gear drive cases in production for passenger cars.

Some off-road driving enthusiasts modify their vehicles to use gear-driven transfer cases, accepting the additional weight and noise to gain the extra strength they generally provide.

It is located further down the driveline than a married transfer case and connected to the transmission output shaft by a short driveshaft.

Manual Shift On-the-Fly transfer cases have a selector lever on the driver's side floor transmission hump and may also have either two sealed automatic front axle locking hubs or two manual front axle hub selectors of "LOCK" and "UNLOCK" or "FREE".

Electronic Shift On-the-Fly (ESOF) transfer cases have a dash-mounted selector switch or buttons with front sealed automatic locking axle hubs or drive flanges.

Inside of a 231 New Process Gear transfer case. Part-time/Manual, shift on the fly
The levers on a Kubota tractor for selecting between 2WD and 4WD (left) and high and low gear ranges (right) are connected to the transfer case . The transfer case is currently in high-range, rear-wheel-drive.