1970 Chevelle Rear Axle Date & Ratio Codes

 

1964

1965

1966

1967

1968

1969

1970

1971

1972

 

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 - 3.36:1 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. See bottom of page for photo examples.

Casting Numbers:
12-Bolt Casting #3969278 - very early 1970s have been reported with #3959038 units.
10-Bolt Casting #3969277

 

Casting date decode here →

 

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	3.08:1 - 10-bolt (L14/307 & L22/250)*
CCB	3.36:1 - 10-bolt
CCD	3.07:1 - 12-bolt Positraction
CCE	3.08:1 - 10-bolt Positraction
CCF	3.31:1 - 12-bolt Positraction (L34/402 & L48/350-4)*
CCG	3.36:1 - 10-bolt Positraction
CCH	2.73:1 - 12-bolt Positraction (L48/350-4)*
CCL	2.56:1
CCM	2.56:1 - Positraction
CCN	2.56:1
CCO	2.56:1 - Positraction (El Camino L34/396)*
CCP	2.73:1 - 10-bolt (L14/307)*
CCW	3.31:1 - 12-bolt (L34/402 & LS3/402 M.C.)*
CCX	3.07:1 - 12-bolt
CGA	2.56:1 - 10-bolt (L65/350-2)*
CGB	2.56:1 - 10-bolt Heavy Duty Positraction (L65/350-2)*
CGC	2.73:1 - Heavy Duty
CGD	2.73:1 - Heavy Duty Positraction
CGE	3.08:1 - 10-bolt Heavy Duty
CGF	3.08:1 - 10-bolt Heavy Duty Positraction
CGG	3.36:1 - 10-bolt Heavy Duty
CGI	3.36:1 - 10-bolt Heavy Duty Positraction
CKC	2.73:1 - Positraction
CKD	2.73:1 - 12-bolt (L48/350-4 & LS3/402)*
CKF	3.55:1 - 12-bolt Positraction (L78)*
CKJ	3.55:1 - 12-bolt (L78/402)*
CKK	4.10:1 - 12-bolt Positraction (L78/402)*
CRJ	2.56:1
CRK	2.56:1 - 12-bolt Positraction (Monte Carlo LS5/454)*
CRL	3.07:1 - 12-bolt
CRM	3.07:1 - 12-bolt
CRU	3.31:1 - 12-bolt (LS5/454 & LS6/454)*
CRV	3.31:1 - 12-bolt Positraction (LS5/454 & LS6/454)*
CRW	4.10:1 - 12-bolt Heavy Duty (LS6/454)*

Positraction 4.10:1 ring gear

 

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, Detroit, Michigan
K	McKinnon Industries (GM of Canada)
W	Warren, Michigan

 

CCF - Positraction 3.31:1 - August 21, Buffalo, N.Y. plant.

 

CKF - Positraction 3.55:1 - October 7, Buffalo, N.Y. plant.

 

CCW - 3.31:1 - September 18, Buffalo, N.Y. plant.

 

CCP - 2.73:1 - October 1, Warren, MI. plant.

 

CRU - 3.31:1 - October 20, Buffalo, N.Y. plant, 1st shift
(Suspect stamping as the letter "C" is not consistent with others of this year).

 

CCF - Positraction 3.31:1 - November 6, Buffalo, N.Y. plant, 1st shift.

 

CCF - Positraction 3.31:1 - November 10, McKinnon - Courtesy Dane Belden.

 

CCF - Positraction 3.31:1 - November 20, Buffalo, N.Y. plant, 1st shift.

 

CRV - Positraction 3.31:1 - November 26, Buffalo, N.Y. plant, 1st shift.

 

CRV - Positraction 3.31:1 - December 05, Buffalo, N.Y. plant, 2nd shift.

 

CRV - Positraction 3.31:1 - December 08, Buffalo, N.Y. plant, 2nd shift.

 

CRV - Positraction 3.31:1 - December 22, Buffalo, N.Y. plant, 1st shift.

 

CCW - 3.31:1 - January 9, Buffalo, N.Y. plant, 2nd shift.

 

CRW - Positraction 4.10:1 - February 12, Buffalo, N.Y. plant, 1st shift
(Suspect stamping as the letter "C" is not consistent with others of this year).

 

CCW - 3.31:1 - February 16, Buffalo, N.Y. plant, 2nd shift.

 

CCH - Positraction 2.73:1 - February 18, Buffalo, N.Y. plant, 1st shift.

 

CCW - 3.31:1 - February 27, Buffalo, N.Y. plant, 1st shift.

 

CKD - 2.73:1 - March 20, Buffalo, N.Y. plant, 1st shift.

 

CCF - Positraction 3.31:1 - March 25, Buffalo, N.Y. plant, 1st shift.

 

CCF - Positraction 3.31:1 - April 8, Buffalo, N.Y. plant, 2nd shift.

 

CRV - Positraction 3.31:1 - April 10, Buffalo, N.Y. plant, 2nd shift.

 

CKD - 2.73:1 - April 15, Buffalo, N.Y. plant, 2nd shift.

 

CCF - Positraction 3.31:1 - May 21, Buffalo, N.Y. plant, 1st shift.

 

CRW - Positraction 4.10:1 - May 27, Buffalo, N.Y. plant, 2nd shift.

 

CGA - 2.56:1 - June 02, Buffalo, N.Y. plant, 1st shift.

 

CRW - Positraction 4.10:1 - June 03, Buffalo, N.Y. plant, 2nd shift.

 

CF - Positraction 3.31:1 - June 27, Buffalo, N.Y. plant (Appears someone was lazy and only stamped this CF instead of CCF).

 

Casting Date Examples

Casting date example of I 8 9 for September 8, 1969.

 

Casting date example of J 10 9 for October 10, 1969.

 

Casting date example of K 10 9 for November 10, 1969.

 

B 27 0 for February 27, 1970.

 

C 5 0 for March 5, 1970.

 

Casting date example of E 8 0 for May 8, 1970.

 

Casting date example of E 11 0 for May 11, 1970.

 

Casting date example of F 24 0 for June 24, 1970.

 

Casting date example of G 28 0 for July 28, 1970.

 

Casting Number Examples

1970-1972 - Variations of casting number 3969278.

 

* 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.

 

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