The Chevy’s rear axle code contains information on the vehicle’s gear ratio, date of manufacture and the rear axle assembly plant. It consists of a two or three letter prefix representing the gear ratio code, four-digit number for the assembly date in a month/day format and a single letter denoting the manufacturing location. In some cases, there is an additional number for the assembly shift. The GM website offers more information on gear ratio identification codes for respective years.
The prefix on the code consists of two letters for Chevrolet vehicles built in 1969 and earlier and three letters for later models. The code is located on the passenger side of the axle tube. In some cases, tracing the code is hard due to grease, grime and mud on the axle. Clean the axle using chalk, a grease pen or damp towel rather than abrasive brushes.
Identifying the rear axle code is crucial. It adds significant value to the vehicle, especially for specialty Chevy cars. The code is original to the vehicle and should match the original paperwork. It also comes in handy during servicing, especially when ordering replacement parts. However, do note that the number may be missing or incorrect due to previous axle replacements.