1964 Chevelle
1965 Chevelle
1966 Chevelle
1967 Chevelle
1968 Chevelle
1969 Chevelle
1970 Chevelle
1971 Chevelle
1972 Chevelle1967 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 font of right axle tube either adjacent to the carrier housing or about 8" - 10" inboard from the backing plates.
Example: CB1012W decodes to CB - 3.36:1, 1025 - Month [Oct] and Day [12], W - Warren (B=Buffalo, G=Chevrolet Gear & Axle, K=McKinnon Industries). See bottom of page for photo examples.
Casting Numbers:
12-Bolt Casting #N3894939 (narrow early model year),
#NF3917124 (wide late model year)*
10-Bolt Casting #3894938N
* (Note: For what it's worth, ALL 67 rear ends I've ever seen were the narrow variety and used the spring cup like 68-72 but were narrower like the 64-66. I do have photos of a June 1967 cast #3917124 rear end but the assembly date is October - obviously for a 1968 model year Chevelle. However, a June 1967 casting date rear end such as this might have found its way into very late 1967 model year Chevelles as well and could be the basis for the statement in an article from Car Craft magazine some years ago titled "Inside 64-72 A-Bodies".)
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 | 2.73:1 - Positraction |
| CI | 3.73:1 - Positraction |
| CJ | 3.07:1 - w/Metallic Brakes |
| CK | 3.07:1 - Positraction w/Metallic Brakes |
| CL | 2.73:1 - Positraction |
| CM | 2.73:1 - Positraction w/Metallic Brakes |
| CN | 3.31:1 - w/Metallic Brakes |
| CO | 3.31:1 - Positraction w/Metallic Brakes |
| CR | 3.70:1 - Positraction |
| CS | 2.56:1 - w/Metallic Brakes |
| CT | 3.73:1 - w/Metallic Brakes |
| CU | 3.73:1 - Positraction w/Metallic Brakes |
| CV | 3.70:1 |
| CW | 3.31:1 |
| CX | 3.07:1 |
| CY | 3.07:1 |
| CZ | 2.73:1 |
| KA | 3.55:1 |
| KB | 3.55:1 - Positraction |
| KC | 2.73:1 - Positraction |
| KD | 2.73:1 |
| KE | 2.56:1 - Positraction |
| KF | 3.55:1 - Positraction |
| KG | 3.55:1 - Positraction w/Metallic Brakes |
| KH | 3.55:1 - w/Metallic Brakes |
| KI | 2.56:1 - Positraction w/Metallic Brakes |
| KJ | 3.55:1 |
| KK | 4.10:1 - Positraction |
| KL | 4.10:1 - w/Metallic Brakes |
| KM | 4.56:1 - Positraction |
| KN | 4.56:1 - w/Metallic Brakes |
| KO | 4.88:1 - Positraction |
| KP | 4.88:1 - w/Metallic Brakes |
| KQ | 2.73:1 - w/Metallic Brakes |
| KR | 2.73:1 - Positraction w/Metallic Brakes |
| KS | 3.07:1 - w/Metallic Brakes |
| KT | 3.07:1 - Positraction w/Metallic Brakes |
| KU | 3.31:1 - w/Metallic Brakes |
| KV | 3.31:1 - Positraction |
| KW | 2.73:1 - Positraction |
| KX | 3.07:1 - Positraction |
| KY | 3.31:1 |
| KZ | 3.31:1 |
| Assembly Month - 1st and 2nd numbers | |||
| 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 pigtail ends of the coil spring and how it is attached to
the rear axle housing compared to 1964/1966 units.
The gear ratio code, date, and rear axle assembly plant are generally
stamped into the right (passenger side) axle housing facing forward
and exact locations may vary slightly. This is an example from a 1967
Chevelle and is stamped CB 1012 W. The "CB" letters
are the original ID code for a 3.36:1 ratio, 1012 is the assembly date
of October 12, and the "W" indicates the plant code for Warren,
MI. This identification may not always be stamped clearly and the area
is often covered with years of road grime so it may take some scrubbing
to reveal it.
CB - 3.36:1, October 12, Warren. MI.
CZ - 2.73:1, December 21, Buffalo, N.Y.
KW - Positraction 2.73:1, April 18, Buffalo, N.Y.
KO - 4.88:1, September 28, 1966 - Courtesy Jeff Helms
Casting Date Examples
Casting date example of F 21 7 for June 21, 1967
Casting date example of L 14 7 for December 14, 1967
Casting Number Examples
1967-1969 - Variations of casting number 3917124
Want more in-depth information on 1966/1967 Chevelles? Try my
1966/1967 Chevelle
Reference CD.
