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. CF = 3.31 Positraction
0706 = July 6
B = Buffalo, N.Y. manufacturing location | 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 | | CK | 3.07:1 | | CL | 2.73:1 | | CM | 2.73:1 ~ Positraction | | CN | 3.31:1 | | CO | 3.31:1 ~ Positraction | | CP | 2.73:1 | | CQ | 2.56:1 | | CR | 3.70:1 ~ Positraction | | CS | 2.56:1 | | CT | 3.73:1 | | 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 | | FH | 2.73:1 ~ small ring gear (Note 1) | | FI | 2.73:1 ~ Positraction, small ring gear (Note 1) | | FJ | 3.08:1 | | FK | 3.08:1 ~ Positraction | | FL | 3.36:1 | | FM | 3.36:1 ~ Positraction | | FN | 3.55:1 ~ small ring gear (Note 1) | | FO | 3.55:1 ~ Positraction, small ring gear (Note 1) | | FP | 3.70:1 | | FQ | 3.70:1 ~ Positraction | | K2 | 3.55:1 | | K3 | 3.55:1 ~ Positraction | | K4 | 3.73:1 | | K5 | 3.73:1 ~ Positraction | | K6 | 4.10:1 ~ Positraction | | K7 | 4.56:1 ~ Positraction | | K8 | 4.88:1 ~ Positraction | | KA | 3.55:1 ~ small ring gear (Note 1) | | KB | 3.55:1 ~ Positraction, small ring gear (Note 1) | | KC | 2.73:1 ~ Positraction, small ring gear (Note 1) | | KD | 2.73:1 ~ large ring gear (Note 1) | | KE | 2.56:1 ~ Positraction | | KF | 3.55:1 ~ Positraction, large ring gear (Note 1) | | KG | 3.55:1 ~ Positraction | | KH | 3.55:1 | | KI | 2.56:1 | | KJ | 3.55:1 ~ large ring gear (Note 1) | | KK | 4.10:1 ~ Positraction | | KL | 4.10:1 ~ Positraction | | KM | 4.56:1 ~ Positraction | | KN | 4.56:1 ~ Positraction | | KO | 4.88:1 ~ Positraction | | KP | 4.88:1 ~ Positraction | | KQ | 2.73:1 | | KR | 2.73:1 ~ Positraction | | KS | 3.07:1 | | KT | 3.07:1 ~ Positraction | | KU | 3.31:1 | | KV | 3.31:1 ~ Positraction | | KW | 2.73:1 ~ w/Metallic Brakes | | KX | 3.07:1 ~ Positraction | | KY | 3.31:1 ~ Positraction | | KZ | 3.31:1 |
Note 1:
Just what constitutes a 'small' ring gear or 'large' ring gear is uncertain. My
Chevrolet Parts and Accessories Catalog, circa 1972, only shows the gear ratio
service part numbers so it is quite possible one or the other was discontinued
in favor of a 'service' part. Anyone with knowledge of the differences, please
contact me so I can share the information with all.
| 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 Rear Axle Assembly Plant - 5th letter | | Code | Assembly Plant | | *B | *Buffalo, NY | | G | Chevrolet Gear & Axle | | W | Warren, MI | | K | McKinnon Industries |
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