The ratio between the driveshaft or transmission output shaft rpm and the drive-wheel axle shaft rpm. For example, if the ratio is 4.00:1 the driveshaft rotates four times for each rotation of the rear axle differential gear, the axle shafts and the wheels.
The reduction ratio, found in the gearset of a drivetrain, that is furthest removed from the engine. Typically, the differential ratio.
A fluid coupling consists of two fan-like impellers in a sealed, oil-filled housing. The input "fan" churns the oil, and the churning oil, in turn, twirls the output "fan." Such a coupling allows some speed difference between its input and output shafts. The automatic transmission's torque converter is based on the fluid coupling principle.
The number of turns the rear wheels make in relation to the number of turns the drive shaft makes.
The rotational speed of the transmission output shaft divided by the speed of the driven wheel shafts.
Speed ratio between the propeller shaft and the driven wheel axle shaft. A low ratio has lower engine speed, reduced performance ability and lower engine revolutions per mile so fuel economy is improved. A higher ratio has a higher engine speed, increased performance ability, better acceleration and higher fuel consumption.
The ratio between the drive pinion and ring gear.