Step by step explanation on how an automotive differential works. This information pertains to all vehicles.

Step 1 - An automotive differential is used to evenly distribute engine power to the drive wheels. These differentials exist in every vehicle which drive either front or rear wheels. Some vehicles utilizes front and rear wheel drive commonly known as four wheel drive. This is achieved through the use of a transfer case, which separates engine power into two drive shafts.

Automotive Differential

Step 2 - Inside the differential is a ring gear which is driven by a pinion gear (not in view.) This particular differential is equipped with a locker, which can sense wheel slip to couple the spider gears forcing both drive wheels to work as one.

Ring Gear and Locker

Step 3 - A pinion shaft is used to hold the spider gears in place while positioning each axle as to hold a retainer clip in place.

Pinion Shaft

Step 4 - A differential is equipped with a set of spider gears (four) which are used to allow each wheel to turn independently of each other. This operation is necessary for the vehicle to turn smoothly as the inner wheel will travel less distance than the outer wheel.

Spider Gears

Step 5 - Some differentials are designed with an axle retainer clip which is used to hold the axle in place.

Axle Retainer Clip


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-07)