Transmissions: Final Drive & Drive Shafts: Basic layouts
Front-wheel drive layout
 
In front wheel drive vehicle layouts, the engine can be mounted transversely or longitudinally. Drive is transmitted to the front wheels through a transaxle.
 
Rear-wheel drive layout
 
In a conventional rear-wheel-drive layout, the engine and transmission are mounted longitudinally at the front of the vehicle and drive is transmitted to a rear axle assembly by a propeller shaft.
 
Four-wheel drive layout
 
In a conventional four-wheel-drive vehicle, propeller shafts connect a transfer case at the rear of the transmission to final drive units on both front and rear axles.
 
All-wheel drive layout
 
In a conventional full-time four-wheel drive vehicle, a third differential is located in the transfer case.
 
4WD vs AWD
 
Four-wheel drive (4WD) and all-wheel drive (AWD) are different types of automotive drive systems.
 
Differential
 
A device, usually consisting of gears, for supplying equal torque to the driving wheels, even as they rotate at different speeds.