REAR AXLE IDENTIFICATION

The rear axle identification code consists of a three letter prefix indicating the manufacturing plant and gear ratio, four digits indicating the assembly date as month/day, and a single letter suffix indicating the manufacturing location. The identification code should be stamped on the bottom or front left or right axle tube either adjacent to the carrier housing or about 8" - 10" inboard from the backing plates.

* Some assembly plants have been found to code the axle ratio first, then the manufacturing location such as GNC where GN is the ratio (3.08:1) and C is the assembly plant.

C = Buffalo, N.Y. manufacturing location*
RU = 3.31:1*
223 = August 10, 1970

Rear Axle Assembly Plant - First character

Code Assembly Plant
C Buffalo, N.Y.
G Detroit Gear & Axle
K McKinnon Industries (GM of Canada)
W Warren, MI.

Prefix Axle Ratio
GD 2.73:1 ~ Positraction
GF 3.08:1
CH 2.73:1 ~ Positraction
GA 2.56:1
GC 2.73:1
GG 3.36:1
GB 2.56:1 ~ Positraction
GI 3.36:1 ~ Positraction
KD 2.73:1
CW 3.31:1
CF 3.31:1 ~ Positraction
*RU 3.31:1
RV 3.31:1 ~ Positraction
RW 4.10:1 ~ Positraction
GH 2.73:1
GN 3.08:1

Assembly Date - 3-digit number is Julian day beginning with January 1, 1970.  The day 223 is the 223rd day of 1970, or August 10, 1970.