1970 Chevelle Rear Axle Identification

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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

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.

PrefixAxle Ratio
CCA3.08:1 ~ 10-bolt (L14/307 & L22/250)*
CCB3.36:1 ~ 10-bolt
CCD3.07:1 ~ 12-bolt Positraction
CCE3.08:1 ~ 10-bolt Positraction
CCF3.31:1 ~ 12-bolt Positraction (L34/402 & L48/350-4)*
CCG3.36:1 ~ 10-bolt Positraction
CCH2.73:1 ~ 12-bolt Positraction (L48/350-4)*
CCL2.56:1
CCM2.56:1 ~ Positraction
CCN2.56:1
CCO2.56:1 ~ Positraction (El Camino L34/396)*
CCP2.73:1 ~ 10-bolt (L14/307)*
CCW3.31:1 ~ 12-bolt (L34/402 & LS3/402 M.C.)*
CCX3.07:1 ~ 12-bolt
CGA2.56:1 ~ 10-bolt (L65/350-2)*
CGB2.56:1 ~ 10-bolt Heavy Duty Positraction (L65/350-2)*
CGC2.73:1 ~ Heavy Duty
CGD2.73:1 ~ Heavy Duty Positraction
CGE3.08:1 ~ 10-bolt Heavy Duty
CGF3.08:1 ~ 10-bolt Heavy Duty Positraction
CGG3.36:1 ~ 10-bolt Heavy Duty
CGI3.36:1 ~ 10-bolt Heavy Duty Positraction
CKC2.73:1 ~ Positraction
CKD2.73:1 ~ 12-bolt (L48/350-4 & LS3/402)*
CKF3.55:1 ~ 12-bolt Positraction (L78)*
CKJ3.55:1 ~ 12-bolt (L78/402)*
CKK4.10:1 ~ 12-bolt Positraction (L78/402)*
CRJ2.56:1
CRK2.56:1 ~ 12-bolt Positraction (Monte Carlo LS5/454)*
CRL3.07:1 ~ 12-bolt
CRM3.07:1 ~ 12-bolt
CRU3.31:1 ~ 12-bolt (LS5/454 & LS6/454)*
CRV3.31:1 ~ 12-bolt Positraction (LS5/454 & LS6/454)*
CRW4.10:1 ~ 12-bolt Heavy Duty (LS6/454)*

CHEVELLESTUFF  All Rights Reserved
Positraction 4.10:1 ring gear

Assembly Month - 1st and 2nd numbers
NumberMonthNumberMonth
01January02February
03March04April
05May06June
07July08August
09September10October
11November12December

Assembly Day - 3rd and 4th numbers
01...31

Rear Axle Assembly Plant - 5th letter

CodeAssembly Plant
BBuffalo ~  New York
GChevrolet Gear & Axle
WWarren ~  Michigan
KMcKinnon Industries

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - August 21, Buffalo

CHEVELLESTUFF  All Rights Reserved
CKF ~ Positraction 3.55:1 ~ October 7, Buffalo

CHEVELLESTUFF  All Rights Reserved
CCW ~ 3.31:1 - September 18, Buffalo

CHEVELLESTUFF  All Rights Reserved
CCP ~ 2.73:1 - October 1, Warren, MI.

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

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

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - November 10, McKinnon ~ Courtesy Dane Belden

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - November 20, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CRV ~ Positraction 3.31:1 - November 26, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CRV ~ Positraction 3.31:1 - December 05, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CRV ~ Positraction 3.31:1 - December 08, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CRV ~ Positraction 3.31:1 - December 22, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CCW ~ 3.31:1 - January 9, Buffalo, 2nd shift

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

CHEVELLESTUFF  All Rights Reserved
CCW ~ 3.31:1 - February 16, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CCH ~ Positraction 2.73:1 - February 18, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CCW ~ 3.31:1 - February 27, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CKD ~ 2.73:1 - March 20, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - March 25, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - April 8, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CRV ~ Positraction 3.31:1 - April 10, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CKD ~ 2.73:1 - April 15, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CCF ~ Positraction 3.31:1 - May 21, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CRW ~ Positraction 4.10:1 ~ May 27, Buffalo, 2nd shift

CHEVELLESTUFF  All Rights Reserved
CGA ~ 2.56:1 - June 02, Buffalo, 1st shift

CHEVELLESTUFF  All Rights Reserved
CRW ~ Positraction 4.10:1 - June 03, Buffalo, 2nd shift

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

Casting Date Examples

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

CHEVELLESTUFF  All Rights Reserved
Casting date example of J 10 9 for October 10, 1969

CHEVELLESTUFF  All Rights Reserved
Casting date example of K 10 9 for November 10, 1969

CHEVELLESTUFF  All Rights Reserved
B 27 0 for February 27, 1970

CHEVELLESTUFF  All Rights Reserved
C 5 0 for March 5, 1970

CHEVELLESTUFF  All Rights Reserved
Casting date example of E 8 0 for May 8, 1970

CHEVELLESTUFF  All Rights Reserved
Casting date example of E 11 0 for May 11, 1970

CHEVELLESTUFF  All Rights Reserved
Casting date example of F 24 0 for June 24, 1970

CHEVELLESTUFF  All Rights Reserved
Casting date example of G 28 0 for July 28, 1970

Casting Number Examples

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CHEVELLESTUFF  All Rights Reserved
CHEVELLESTUFF  All Rights Reserved
CHEVELLESTUFF  All Rights Reserved
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.