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Decoding Rear Axle
1970
The 1970 Monte Carlo is a year that is unique to the first generation of Monte Carlo’s. It is the only year that Chevrolet had the three-digit rear axle ratio identifier “CCH for example all of them started with C for Chevrolet” and the only year that they had a month and day code “01 23 known as January twenty third” for the Monte Carlo. The information that will follow will be from several sources and they will very in accuracy. So believe only what you can confirm as the truth. Two out of the three books are very similar to each other and are approved by general motors but they do not guarantee their accuracy.
1970 example code
C GB 10 05 B E1.) Vehicle installed in:
C= Chevrolet
2.) Rear Axle Types:
1970 AXLE CODES & RATIOS
From Chiltons manual:
CCA 3.08 CCD 3.07 CCE 3.08 CCF 3.31 CCH 2.73 CCN 2.56 CCO 2.56 CCP 2.73 CCW 3.31 CCX 3.07 CGA 2.56 CGB 2.56 CGC 2.73 CGD 2.73 CGG 3.36 CGI 3.36 CKC 2.73 CKD 2.73 CKF 3.55 CKJ 3.55 CKK 4.10 CRJ 2.56 CRK 2.56 CRU 3.31 CRV 3.31 CRW 4.10 (CF 3.31 CW 3.31 KD 2.73 CH 2.73) “ The last four codes most likely were a mistake from the author because they should be “CCF, CCW, CKD, CCH”
From Haynes manual:
CCG 3.36 CCP 2.73 CGF 3.08 CCH 2.56 CCW 3.31 CGG 3.36 CCL 2.56 CCX 3.07 CGI 3.36 CCM 2.56 CGA 2.56 CKC 2.73 CCE 3.08 CCN 2.56 CGB 2.56 CKD 2.73 CCF 3.31 CCO 2.56 CGC 2.73 CKF 3.55 CGD 2.73 CGE 3.08 CKJ 3.55 CKK 4.10 CRJ 2.56 CRK 2.56 CRL 3.07 CRM 3.07 CRU 3.31 CRV 3.31 CRW 4.10 (CF 3.08 WF 3.23 CH 2.73 XC 2.78 CW 3.31 XE 3.08 KD 2.73 XF 2.73) The last eight are the same thing as the Chiltons manual most likely a mistake was made but just in case there they are.
From the Chevrolet by the numbers book:
CCA 3.08 CCB 3.36 CCD 3.07 CCE 3.08 CCF 3.31 CCG 3.36 CCH 2.73 CCL 2.56 CCM 2.56 CCN 2.56 CCO 2.56 CCP 2.73 CCW 3.31 CCX 3.07 CGA 2.56 CGB 2.56 CGC 2.73 CGD 2.73 CGE 3.08 CGF 3.08 CGG 3.36 CGI 3.36 CKC 2.73 CKD 2.73 CKF 3.55 CKJ 3.55 CKK 4.10 CRJ 2.56 CRK 2.56 CRL 3.07 CRM 3.07 CRU 3.31 CRV 3.31 CRW 4.10
3.) Month Codes:
1= January 2=Febuary 3=March 4=April 5=May 6=June
7=July 8=August 9=September 10= October 11=November 12=December
4.) Day Codes:
05= fifth day of the month “1-31 days”
5.) Plant Source:
G= Detroit Gear & Axle B= Buffalo NY W= Warren MI
6.) Positraction sources:
D= Dana Positraction Differential E= Eaton Positraction Differential W= Warren Motive
If your car did not have a positraction source code it does not have positraction.
1971 - 1972
The 1971 Monte Carlo is a year that is unique to the first generation of Monte Carlo’s. It is the year that Chevrolet went to the two-digit rear axle ratio identifiers “CH for example” and the first year they used a Julian date “001-365.” The 1972 Monte Carlo is a year that is unique to the first generation of Monte Carlo’s. It is the year that Chevrolet did not make a super sport but instead made a Monte Carlo Custom. As stated before the information will be from several sources and they will very in accuracy. So believe only what you can confirm as the truth. Two out of the three books are very similar to each other and are approved by general motors but they do not guarantee their accuracy.
1971 - 1972 example code
KD C 314 2 E1.) Rear Axle Types:
1971 AXLE CODES & RATIOS
From the Chiltons manual:
CF 3.31 CW 3.31 GA 2.56 GB 2.56 GC 2.73 GD 2.73 GF 3.08 GG 3.36 GH 2.73 GI 3.36 GN 3.08 KD 2.73 RU 3.31 RV 3.31 RW 4.10
From the Haynes manual:
CW 3.31 GC 2.73 GD 2.73 GF 3.08 GG 3.36 GH 2.73 GI 3.31 GN 3.08 KD 2.73 RU 3.31 RV 3.31 RW 4.10
From the Chevrolet by the numbers book:
CF 3.31 CH 2.73 CW 3.31 GA 2.56 GB 2.56 GC 2.73 GD 2.73 GF 3.08 GG 3.36 GH 2.73 GI 3.36 GN 3.08 KD 2.73 RU 3.31 RV 3.31 RW 4.10
1972 AXLE CODES & RATIOS
From the Chiltons manual:
CF 3.31 CW 3.31 GF 3.08 GG 3.36 GH 2.73 GI 3.36 GN 3.08 RU 3.31 RV 3.31 RW 4.10
From the Haynes manual:
CW 3.31 GC 2.73 GD 2.73 GF 3.08 GG 3.36 GH 2.73 GI 3.31 GN 3.08 RU 3.31 RV 3.31 RW 4.10
From the Chevrolet by the numbers book:
CF 3.31 CH 2.73 CW 3.31 GC 2.73 GD 2.73 GF 3.08 GG 3.36 GH 2.73 GI 3.36 GN 3.08 KD 2.73 RU 3.31 RV 3.31
2.) Plant Codes:
B= Buick
C= Buffalo
G= Detroit Gear & Axle
K= GM of Canada
O= Oldsmobile
P= Pontaic
W= Warren MI
3.) Julian Date/Day of Year:
001-365
4.) Shift Codes:
1= 1ST Shift
2= 2ND Shift
3= 3RD Shift
5.) Positraction sources:
D= Dana Positraction Differential
E= Eaton Positraction Differential
W= Warren Motive Positraction Carrier
If your car did not have a positraction source code it does not have positraction.
Thank You Alex for taking the time to research, and write all of this out for us.