1965 El Camino Rear Axle Identification
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 Positraction, 1025 ~ Month [Oct] and Day [25], B ~ Buffalo (G=Chevrolet Gear & Axle, W=Warren, K=McKinnon Industries). See bottom of page for more examples.
Casting Numbers:
12-Bolt Casting #3859140N
10-Bolt Casting #3859139N
10-Bolt Casting #3863495N *
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 |
| CB | 3.36 |
| CC | 3.73 |
| CD | 3.07 ~ Positraction |
| CE | 3.08 ~ Positraction |
| CF | 3.31 ~ Positraction |
| CG | 3.36 ~ Positraction |
| CH | 3.70 ~ Positraction w/Metallic Brakes |
| CI | 3.73 ~ Positraction |
| CJ | 3.07 ~ Metallic Brakes |
| CK | 3.07 ~ Positraction w/Metallic Brakes |
| CL | 3.08 ~ Metallic Brakes |
| CM | 3.08 ~ Positraction w/Metallic Brakes |
| CN | 3.31 ~ Metallic Brakes |
| CO | 3.31 ~ Positraction w/Metallic Brakes |
| CP | 3.36 ~ Metallic Brakes |
| CQ | 3.36 ~ Positraction w/Metallic Brakes |
| CH | 3.70 ~ Metallic Brakes |
| CR | 3.70 ~ Positraction |
| CS | 3.70 ~ Positraction w/Metallic Brakes |
| CT | 3.73 ~ Metallic Brakes |
| CU | 3.73 ~ Positraction w/Metallic Brakes |
| CV | 3.70 ~ Overdrive |
| CW | 3.31 ~ "327" w/Air Conditioning |
| CX | 3.07 ~ "327" |
| GA | 3.31 ~ Heavy Duty |
| GB | 2.73 ~ 327 w/Powerglide |
| GC | 2.73 ~ Positraction |
| GD | 2.73 ~ Metallic Brakes |
| GE | 2.73 ~ 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 |
CX 0909 B ~ 3.07, September 9, Buffalo
CF 0609 B E ~ Positraction 3.31, June 9, Buffalo, Eaton
CB 0625 ~ 3.36, June 25
CG 0629 B ~ Positraction 3.36, June 29, Buffalo
* Housing with casting number
3863495N. These seem to be a relatively rare rear end casting
number for 1965 10-bolt Chevelles and may, MAY, be another GM line.
