In front wheel drive vehicles the engine can be mounted transversely, or longitudinally.
Drive reaches the front wheels through a transmission and final drive unit called a transaxle.
In transverse applications the transaxle is normally mounted at the rear of the engine and a primary shaft engages with the splines of the clutch center plate.
When a gear is engaged, drive is transferred to a secondary shaft, and, through a secondary shaft pinion, to a helical ring gear attached to the differential case.
Drive is then transferred through the differential gears, to each drive shaft and into each front wheel.
Universal joints are fitted at the inner and outer ends of the shafts to allow for suspension and steering movement.
In this case the engine crankshaft, transaxle shafts and drive shafts, all rotate in-line, which simplifies the final drive arrangement.
Mounting the engine longitudinally, means the drive must be turned through ninety degrees. A crown wheel and pinion is commonly used for this purpose.
The transaxle can be mounted under the engine and the drive transferred by a chain, from the clutch shaft to the transmission input shaft.
The final drive bevel pinion is formed on the output shaft and meshes with a crown wheel attached to the differential case.
The drive is transferred through ninety degrees, to the drive shafts and to the road wheels.
