1964 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. It's not certain if all rear axle codes available for Chevelles were or were not also available for the El Camino so all rear axle codes are listed here.
Example: YB 1025 decodes to YB ~ 3.36, 1025 ~ Month [Oct] and Day [25]
Casting Numbers:
10-Bolt Casting #3839390N
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 |
| LA | 3.08 ~ 3 or 4-speed |
| LB | 3.36 ~ 3 or 4-speed |
| LG | 3.08 ~ Positraction |
| LH | 3.36 ~ Positraction |
| YA | 3.08 ~ 3 or 4-speed |
| YB | 3.36 ~ 3 or 4-speed |
| YG | 3.08 ~ Positraction |
| YH | 3.36 ~ Positraction |
| ZA | 3.08 ~ 3 or 4-speed |
| ZB | 3.36 ~ 3 or 4-speed |
| ZC | 3.08 ~ w/Metallic Brakes |
| ZD | 3.36 ~ w/Metallic Brakes |
| ZE | 3.08 ~ Positraction w/Metallic Brakes |
| ZF | 3.36 ~ Positraction w/Metallic Brakes |
| ZG | 3.08 ~ Positraction |
| ZH | 3.36 ~ Positraction |
| ZJ | 3.70 ~ w/Overdrive |
| ZK | 3.70 ~ Positraction |
| ZL | 3.70 ~ w/Metallic Brakes |
| ZM | 3.70 ~ Positraction w/Metallic Brakes |
| 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 ~ New York |
| G | Chevrolet Gear & Axle |
| W | Warren ~ Michigan |
| K | McKinnon Industries |
