1970 El Camino Rear Axle Identification
The rear axle identification code consists of a three 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. The particular engine RPO code is listed in parentheses as found on build sheets.
Example: CGI0629B decodes to CGI ~ 3.36 Positraction, 0629 ~ Month [June] and Day [29], B ~ Buffalo (G=Chevrolet Gear & Axle, W=Warren, K=McKinnon Industries). If a "1" or "2" exists, it indicates the plant shift number.
Casting Numbers:
12-Bolt Casting #3969278
10-Bolt Casting #3969277
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. Codes below are for Chevelle & Monte Carlo.
| Prefix | Axle Ratio |
| CCA | 3.08 ~ 10-bolt (L14/307 & L22/250)* |
| CCB | 3.36 ~ 10-bolt |
| CCD | 3.07 ~ 12-bolt Positraction |
| CCE | 3.08 ~ 10-bolt Positraction |
| CCF | 3.31 ~ 12-bolt Positraction (L34/402, LS6/454)* |
| CCG | 3.36 ~ 10-bolt Positraction |
| CCH | 2.73 ~ 12-bolt Positraction (L48/350-4)* |
| CCL | 2.56 |
| CCM | 2.56 ~ Positraction |
| CCN | 2.56 |
| CCO | 2.56 ~ Positraction |
| CCP | 2.73 ~ 10-bolt (L14/307)* |
| CCW | 3.31 ~ 12-bolt (L34/402 & LS3/402 M.C.)* |
| CCX | 3.07 ~ 10-bolt |
| CGA | 2.56 ~ 10-bolt (L65/350-2)* |
| CGB | 2.56 ~ 10-bolt Heavy Duty Positraction (L65/350-2)* |
| CGC | 2.73 ~ Heavy Duty |
| CGD | 2.73 ~ Heavy Duty Positraction |
| CGE | 3.08 ~ 10-bolt Heavy Duty |
| CGF | 3.08 ~ 10-bolt Heavy Duty Positraction |
| CGG | 3.36 ~ 10-bolt Heavy Duty |
| CGI | 3.36 ~ 10-bolt Heavy Duty Positraction |
| CKC | 2.73 ~ Positraction |
| CKD | 2.73 ~ 12-bolt (L48/350-4 & LS3/402)* |
| CKF | 3.55 ~ 12-bolt Positraction (L78)* |
| CKJ | 3.55 ~ 12-bolt (L78/402)* |
| CKK | 4.10 ~ 12-bolt Positraction |
| CRJ | 2.56 |
| CRK | 2.56 ~ 12-bolt Positraction (LS5/454)* |
| CRL | 3.07 ~ 12-bolt |
| CRM | 3.07 ~ 12-bolt |
| CRU | 3.31 ~ 12-bolt (LS5/454)* |
| CRV | 3.31 ~ 12-bolt Positraction (LS5/454 & LS6/454)* |
| CRW | 4.10 ~ 12-bolt Heavy Duty (LS6/454)* |
| 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 |
CCF ~ Positraction 3.31 - November 6, Buffalo, 1st shift
CRV ~ Positraction 3.31 - December 08, Buffalo, 2nd shift
CRV ~ Positraction 3.31 - December 22, Buffalo, 1st shift
CCH ~ Positraction 2.73 - February 18, Buffalo, 1st shift
CCF ~ Positraction 3.31 - March 25, Buffalo, 1st shift
CCF ~ Positraction 3.31 - April 8, Buffalo, 2nd shift
CCF ~ Positraction 3.31 - May 21, Buffalo, 1st shift
* Engine RPO code and size following the rear axle ratio are taken from build sheets and/or Protect-O-Plates and may not reflect the only engines the rear axle codes came with. Where there are no RPO/engine information following the rear axle code only means I do not have build sheets and/or Protect-O-Plates to verify them.
