1965 Chevelle Rear Axle Identification

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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 #3859140
10-Bolt Casting #3859139
10-Bolt Casting #
3863495 *

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 ~ Positraction w/Metallic Brakes
CI3.73:1 ~ Positraction
CJ3.07:1 ~ Metallic Brakes
CK3.07:1 ~ Positraction w/Metallic Brakes
CL3.08:1 ~ Metallic Brakes
CM3.08:1 ~ Positraction w/Metallic Brakes
CN3.31:1 ~ Metallic Brakes
CO3.31:1 ~ Positraction w/Metallic Brakes
CP3.36:1 ~ Metallic Brakes
CQ3.36:1 ~ Positraction w/Metallic Brakes
CR3.70:1 ~ Positraction
CS3.70:1 ~ Positraction w/Metallic Brakes
CT3.73:1 ~ Metallic Brakes
CU3.73:1 ~ Positraction w/Metallic Brakes
CV3.70:1 ~ Overdrive
CW3.31:1 ~ "327"
CX3.07:1 ~ "327"
GA3.31:1 ~ Heavy Duty
GB2.73:1 ~ 327 w/Powerglide
GC2.73:1 ~ Positraction
GD2.73:1 ~ Metallic Brakes
GE2.73:1 ~ Positraction w/Metallic Brakes
Assembly Month - 1st and 2nd numbers
At least one Warren, MI. rear housing has been found with "8" instead of "08" stamped.
NumberMonthNumberMonth
01January02February
03March04April
05May06June
07July08August
09September10October
11November12December

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

Rear Axle Assembly Plant - 5th letter

CodeAssembly Plant
BBuffalo, New York
GChevrolet Gear & Axle
WWarren, Michigan
KMcKinnon Industries


CA 825 B ~ 3.08:1, August 25, Warren, MI ~ Courtesy Mike Hanson
(note lack of leading 0 (zero) in the date)


CX 0909 B ~ 3.07:1, September 9, Buffalo, NY


CW 0925 B ~ 3.31:1, September 25, Buffalo, NY


CF 0527 E ~ Positraction 3.31:1, May 27 - Eaton Positraction


CF 0609 B E ~ Positraction 3.31:1, June 9, Buffalo, NY - Eaton Positraction


CB 0625 ~ 3.36:1, June 25


CG 0629 B ~ Positraction 3.36:1, June 29, Buffalo, NY

Casting Date Examples


Casting date example of F 4 5 for June 4, 1965

Casting Number Examples


* Housing with casting number 3863495N.  These seem to be a relatively rare rear end casting number for 1965 10-bolt Chevelles.


Courtesy Leslie McFadden - 1965 El Camino
1965 El Camino with N3863495 casting.