1972 Chevelle Rear Axle & Differential Identification

Picture of a rear differential

Casting Numbers

These are the casting numbers used during this production year. If they were used during another year, you will find the additional years listed below.

10 Bolt Housings
Casting Year
3969277NF 1970
3969277NF 1971
3969277NF 1972
12 Bolt Housings
Casting Year
3969278NF 1970
3969278NF 1971
3969278NF 1972

Decoding Rear Axle Codes

The rear axle identification code is stamped on the axle housing on the bottom, front left, or front right axle tube next to the carrier housing or about 8 to 12 inches from the backing plates. This code consists of 6 or 7 digits and characters indicating the stock gear ratio, month/day of assembly, and the assembly plant. Sometimes you will find an extra character stamped near this code, E indicates Eaton positraction.

For example: GFC0681 decodes this way: GF / C / 068 / 1.

Code Gear Ratio Notes
CF 3.31 Positraction
CH 2.73 Positraction
CW 3.31  
GA 2.56  
GC 2.73  
GD 2.73 Positraction
GF 3.08  
GG 3.36  
GH 2.73  
GI 3.36 Positraction
GN 3.08  
KD 2.73  
RU 3.31  
RV 3.31 Positraction
RW 4.10 Positraction
Code Assembly Plant
B Buick
C Chevrolet
G Chevrolet
K McKinnon Industries
M McKinnon Industries
O Oldsmobile
P Pontiac
Code Plant Shift
1 Day Shift
2 Night Shift