1970 Chevelle Rear Axle Identification

[ 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
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 3.08:1 ~ 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)*

CHEVELLESTUFF
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
W Warren ~  Michigan
K McKinnon Industries

CCF ~ Positraction 3.31:1 - August 21, Buffalo
CCF ~ Positraction 3.31:1 - August 21, Buffalo

CHEVELLESTUFF
CKF ~ Positraction 3.55:1 ~ October 7, Buffalo

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

CCF ~ Positraction 3.31:1 - November 6, Buffalo, 1st shift
CCF ~ Positraction 3.31:1 - November 6, Buffalo, 1st shift

CCF ~ Positraction 3.31:1 - November 6, Buffalo, 1st shift
CCF ~ Positraction 3.31:1 - November 20, Buffalo, 1st shift

CRV ~ Positraction 3.31:1 - December 08, Buffalo, 2nd shift
CRV ~ Positraction 3.31:1 - December 08, Buffalo, 2nd shift

CRV ~ Positraction 3.31:1 - December 22, Buffalo, 1st shift
CRV ~ Positraction 3.31:1 - December 22, Buffalo, 1st shift

CCW ~ Positraction 3.31:1 - January 9, Buffalo, 2nd shift
CCW ~ Positraction 3.31:1 - January 9, Buffalo, 2nd shift

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

CCW ~ Positraction 3.31:1 - February 16, Buffalo, 2nd shift
CCW ~ Positraction 3.31:1 - February 16, Buffalo, 2nd shift

CCH ~ Positraction 2.73:1 - February 18, Buffalo, 1st shift
CCH ~ Positraction 2.73:1 - February 18, Buffalo, 1st shift

CCF ~ Positraction 3.31:1 - March 25, Buffalo, 1st shift
CCF ~ Positraction 3.31:1 - March 25, Buffalo, 1st shift

CCF ~ Positraction 3.31:1 - April 8, Buffalo, 2nd shift
CCF ~ Positraction 3.31:1 - April 8, Buffalo, 2nd shift

CKD ~ 2.73:1 - April 15, Buffalo, 2nd shift
CKD ~ 2.73:1 - April 15, Buffalo, 2nd shift

CCF ~ Positraction 3.31:1 - May 21, Buffalo, 1st shift
CCF ~ Positraction 3.31:1 - May 21, Buffalo, 1st shift

CRW ~ Positraction 4.10:1 ~ May 27, Buffalo, 2nd shift
CRW ~ Positraction 4.10:1 ~ May 27, Buffalo, 2nd shift

CRW ~ Positraction 4.10:1 - June 30, Buffalo, 2nd shift
CRW ~ Positraction 4.10:1 - June 0, Buffalo, 2nd shift

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

Casting Date Examples

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

C 5 0 for March 5, 1970
C 5 0 for March 5, 1970

Casting date example of E 8 0 for May 8, 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 E 11 0 for May 11, 1970

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

Casting Number Examples

File Photo - 07/20/2009
CHEVELLESTUFF
File Photo - 07/20/2009
1970-1972 ~ 3969278, 3969378N, 3969278NF

* 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.