1966 Chevelle Rear Axle Identification

[ 1964 ] | [ 1965 ] | [ 1966 ] | [ 1967 ] | [ 1968 ] | [ 1969 ] | [ 1970 ] | [ 1971 ] | [ 1972 ]

The rear axle identification code consists of a two letter prefix indicating the 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.

Example: CG1025B decodes to CG ~ 3.36:1 Positraction, 1025 ~ Month [Oct] and Day [25], B ~ Buffalo (G=Chevrolet Gear & Axle, W=Warren, K=McKinnon Industries). See bottom of page for photo examples.

Casting Numbers:
12-Bolt Casting #3875745N
10-Bolt Casting #3875744N

The casting numbers/letters on rear end housings may have either a prefix or suffix of "N" or "NF" and no reason has been found yet why they may have one or the other.

PrefixAxle Ratio
CA3.08:1
CB3.36:1
CC3.73:1
CD3.07:1 ~ Positraction
CE3.08:1 ~ Positraction
CF3.31:1 ~ Positraction
CG3.36:1 ~ Positraction
CH3.70:1 ~ w/ Metallic Brakes
CI3.73:1 ~ Positraction
CJ3.07:1 ~ w/Metallic Brakes
CK3.07:1 ~ Positraction w/Metallic Brakes
CL3.08:1 ~ w/Metallic Brakes
CM3.08:1 ~ Positraction w/Metallic Brakes
CN3.31:1 ~ w/Metallic Brakes
CO3.31:1 ~ Positraction w/Metallic Brakes
CP3.36:1 ~ w/Metallic Brakes
CQ3.36:1 ~ Positraction w/Metallic Brakes
CR3.70:1 ~ Positraction
CS3.70:1 ~ Positraction w/Metallic Brakes
CT3.73:1 ~ w/Metallic Brakes
CU3.73:1 ~ Positraction w/Metallic Brakes
CV3.70:1 ~ Overdrive
CW3.31:1
CX3.07:1
KC*2.73:1 ~ w/Metallic Brakes
KD*2.73:1 ~ Positraction
KE*2.73:1 ~ Positraction w/Metallic Brakes
KF3.55:1 ~ w/Metallic Brakes
KG3.55:1 ~ Positraction w/Metallic Brakes
KH3.55:1 ~ Positraction
KI2.73:1 ~ "396" w/Powerglide
KJ3.55:1
KK4.10:1 ~ Positraction
KL4.10:1 ~ Positraction w/Metallic Brakes
KM4.56:1 ~ Positraction
KN4.56:1 ~ Positraction w/Metallic Brakes
KO4.88:1 ~ Positraction
KP4.88:1 ~ Positraction w/Metallic Brakes
* Not confirmed
Assembly Month - 1st and 2nd numbers
NumberMonthNumberMonth
01January02February
03March04April
05May06June
07July08August
09September10October
11November12December

Assembly Day - 3rd and 4th numbers
01...31

Rear Axle Assembly Plant - 5th letter

CodeAssembly Plant
BBuffalo, N.Y.
GChevrolet Gear & Axle
WWarren, MI.
KMcKinnon Industries

CHEVELLESTUFF  All Rights Reserved
CW 1112 B decodes to CW=3.31:1, 1112=November 12, B is for Buffalo, N.Y.

Courtesty David Armstrong
CX 0727 B decodes to CX=3.07:1, 0727=July 27, B is for Buffalo, N.Y.

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