1964 Chevelle
1965 Chevelle
1966 Chevelle
1967 Chevelle
1968 Chevelle
1969 Chevelle
1970 Chevelle
1971 Chevelle
1972 Chevelle1966 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 #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.
| 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 - w/ Metallic Brakes |
| CI | 3.73:1 - Positraction |
| CJ | 3.07:1 - w/Metallic Brakes |
| CK | 3.07:1 - Positraction w/Metallic Brakes |
| CL | 3.08:1 - w/Metallic Brakes |
| CM | 3.08:1 - Positraction w/Metallic Brakes |
| CN | 3.31:1 - w/Metallic Brakes |
| CO | 3.31:1 - Positraction w/Metallic Brakes |
| CP | 3.36:1 - w/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 - w/Metallic Brakes |
| CU | 3.73:1 - Positraction w/Metallic Brakes |
| CV | 3.70:1 - Overdrive |
| CW | 3.31:1 |
| CX | 3.07:1 |
| KC* | 2.73:1 - w/Metallic Brakes |
| KD* | 2.73:1 - Positraction |
| KE* | 2.73:1 - Positraction w/Metallic Brakes |
| KF | 3.55:1 - w/Metallic Brakes |
| KG | 3.55:1 - Positraction w/Metallic Brakes |
| KH | 3.55:1 - Positraction |
| KI | 2.73:1 - "396" w/Powerglide |
| KJ | 3.55:1 |
| KK | 4.10:1 - Positraction |
| KL | 4.10:1 - Positraction w/Metallic Brakes |
| KM | 4.56:1 - Positraction |
| KN | 4.56:1 - Positraction w/Metallic Brakes |
| KO | 4.88:1 - Positraction |
| KP | 4.88:1 - Positraction w/Metallic Brakes |
| * Not confirmed Assembly Month - 1st and 2nd numbers |
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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 |
CW 1112 B decodes to CW=3.31:1, 1112=November 12, B is for Buffalo,
N.Y.
CX 0727 B decodes to CX=3.07:1, 0727=July 27, B is for Buffalo, N.Y.
Want more in-depth information on 1966/1967 Chevelles? Try my
1966/1967 Chevelle
Reference CD.
