The open differential is a mechanical device that allows one wheel on an axle to turn faster than the other while ensuring an appropriate distribution of torque between them.Checked 2026-08-16
Differential
The gearset that sends torque to two wheels while allowing them to turn at different speeds in a corner.
Also called: open differential · diff · final drive
What it means
Definition
When a vehicle turns, the outside wheel travels farther than the inside wheel and must rotate faster. A differential passes drive torque to the axle shafts while allowing that speed difference. A basic open differential is the common form; limited-slip and locking differentials change how available torque is shared when traction differs.
Why a buyer cares
What it changes
‘Differential’ names a normal drivetrain component, not a traction feature. A listing must specifically say limited-slip or locking — and the build data should confirm it — before that extra function can be assumed.
In practice
Where you meet it
In drivetrain specifications and service records for differential fluid, seals, bearings or gears.
Two things that look alike
Not the same as
A transfer case divides drive between front and rear axles; a differential allows left and right wheel speeds to differ.
Read next
Related terms
Limited-slip differential (LSD)
A differential that partly resists one wheel spinning while the other has grip.
Transfer case
The unit behind the transmission that splits drive between the front and rear axles.
Axle ratio
How many turns the drive shaft or transmission output makes for one turn of the axle.
Drive shaft and CV joint
Shafts and flexible joints that carry torque from the transmission or differential to the driven wheels.
Where this comes from
Sources
The internal gear arrangement varies; this entry defines the function common to them.