1964 Chevelle Rear Axle & Differential Identification

Picture of a rear differential

Casting Numbers

These are the casting numbers used during this production year. If they were used during another year, you will find the additional years listed below.

10 Bolt Housings
Casting Year
3839390N 1964
12 Bolt Housings
Casting Year

Decoding Rear Axle Codes

The rear axle identification code is stamped on the axle housing on the bottom, front left, or front right axle tube next to the carrier housing or about 8 to 12 inches from the backing plates. This code consists of 7 digits and characters indicating the stock gear ratio, month/day of assembly, and the assembly plant. Sometimes you will find an extra character stamped near this code, E indicates Eaton positraction.

For example: YG0712B decodes this way: YG / 07 / 12 / B.

Code Gear Ratio Notes
LA 3.08 3 or 4 Speed
LB 3.36 3 or 4 Speed
LG 3.08 Positraction
LH 3.36 Positraction
YA 3.08 3 or 4 Speed
YB 3.36 3 or 4 Speed
YG 3.08 Positraction
YH 3.36 Positraction
ZA 3.08 3 or 4 Speed
ZB 3.36 3 or 4 Speed
ZC 3.08 Metallic Brakes
ZD 3.36 Metallic Brakes
ZE 3.08 Positraction w/ Metallic Brakes
ZF 3.36 Positraction w/ Metallic Brakes
ZG 3.08 Positraction
ZH 3.36 Positraction
ZJ 3.70 Overdrive
ZK 3.70 Positraction
ZL 3.70 Metallic Brakes
ZM 3.70 Positraction w/ Metallic Brakes
Code Assembly Plant
B Buffalo, NY
G Chevrolet Gear & Axle
W Warren, MI
K McKinnon Industries