How to Identify Limited Slip on an S10

by Floyd Drake III

Limited slip differentials provide power to both rear wheels instead of just one, as on conventional differentials, or rear ends. Since the mechanics of limited slip differentials are located internally, there is no positive way to visually identify them, so identifying a limited slip differential, which is called positraction by General Motors, requires a manual test, or decoding either the RPO (Regular Production Option) or the VIN (Vehicle Identification Number). Chevrolet S10 models generally use the GM 7.5-inch rear differential, however, certain models were equipped with the GM 8.5-inch differential. Both differentials were available as limited slip, positraction differentials.

Step 1

Raise one rear wheel of the S10 using a jack, jack stands and blocks to prevent the S10 from lurching forward. The wheel only needs to be raised enough to get it off the ground. Once the wheel is raised, shift the transmission into neutral.

Step 2

Turn the wheel by hand. A positraction rear end is difficult or impossible to turn.

Step 3

Locate the RPO code tag attached to the inside of the glove compartment. On the bottom of the RPO tag, there are a series of three-position, alphanumeric codes. Axle designations are found within the "G" grouping, with "G76," "G80" and "G81" used to designate limited slip, or positraction rear differentials.

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