1964 Chevelle
1965 Chevelle
1966 Chevelle
1967 Chevelle
1968 Chevelle
1969 Chevelle
1970 Chevelle
1971 Chevelle
1972 Chevelle1965 Chevelle Rear Axle Date & Ratio Codes
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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. |
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| 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
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Rear Axle Assembly Plant - 5th letter |
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| Code | Assembly Plant |
| B | Buffalo, New York |
| G | Chevrolet Gear & Axle, Detroit, Michigan |
| K | McKinnon Industries (GM of Canada) |
| W | Warren, Michigan |
Note the springs are attached to the axle housing with a plate
secured by a nut and bolt arrangement. Also note the upper and
lower coils are not pigtailed like the 1967 and later springs.
The 1966 Chevelle rear end has the same configuration. This
changed in 1967.
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.
