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.

Prefix Axle Ratio
CA 3.08:1
CB 3.36:1
CC 3.73:1
CD 3.07:1 ~ Positraction
CE 3.08:1 ~ Positraction
CF 3.31:1 ~ Positraction
CG 3.36:1 ~ Positraction
CH 3.70:1 ~ Positraction w/Metallic Brakes
CI 3.73:1 ~ Positraction
CJ 3.07:1 ~ Metallic Brakes
CK 3.07:1 ~ Positraction w/Metallic Brakes
CL 3.08:1 ~ Metallic Brakes
CM 3.08:1 ~ Positraction w/Metallic Brakes
CN 3.31:1 ~ Metallic Brakes
CO 3.31:1 ~ Positraction w/Metallic Brakes
CP 3.36:1 ~ Metallic Brakes
CQ 3.36:1 ~ Positraction w/Metallic Brakes
CR 3.70:1 ~ Positraction
CS 3.70:1 ~ Positraction w/Metallic Brakes
CT 3.73:1 ~ Metallic Brakes
CU 3.73:1 ~ Positraction w/Metallic Brakes
CV 3.70:1 ~ Overdrive
CW 3.31:1 ~ "327"
CX 3.07:1 ~ "327"
GA 3.31:1 ~ Heavy Duty
GB 2.73:1 ~ 327 w/Powerglide
GC 2.73:1 ~ Positraction
GD 2.73:1 ~ Metallic Brakes
GE 2.73:1 ~ 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.
Number Month Number Month
01 January 02 February
03 March 04 April
05 May 06 June
07 July 08 August
09 September 10 October
11 November 12 December

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

Rear Axle Assembly Plant - 5th letter
Code Assembly Plant
B Buffalo, New York
G Chevrolet Gear & Axle
W Warren, Michigan
K McKinnon 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.