G3GM 1973 to 1977 A-bodys. Chevelles, Monte Carlos, El Caminos, Laguna, 442, Cutlass, Malibu, GTO, LeMans, Century, Regal, Grand Am, Grand Prix, Sprint, Gran Sport, Can Am, Hurst-olds, and other 73-77 A-bodies


The most  inclusive G3 rear axle information on the internet! If you have any questions, comments, or corrections, feel free to PM one of the Admins.


RPO Codes:

G80 Axle Positraction, Limited Slip

G81 Positraction Rear Axle

G82 Axle Rear
4.56
G84 Axle Rear
4.10
G86 Axle , Rear, Limited Slip

G87 Ring Gear, 8.50 Inch

G89 Ring Gear, 7.50 Inch

G90 Rear
3.15
G91 Special Highway Rear Axle
3.08
G94 Axle Rear
3.31
G96 Axle Rear
3.55
G97 Axle Rear
2.73
GH0 Axle Rear
3.54
GH2 Axle Rear
2.29
GH3 Axle Rear
2.77
GH4 Axle Rear
2.92
GH7 Axle Rear
2.73
GJ1 Axle Rear
5.38
GJ2 Axle Rear
5.13
GK7 Axle Rear
4.78
GK8 Axle Rear
4.33
GK9 Axle Rear
4.63
GL0 Axle Rear
5.13
GL3 Axle Rear
6.17
GM1 Axle Rear
2.59
GM2 Axle Rear
3.44
GM3 Axle Rear
3.45
GM4 Axle Rear
3.67
GM5 Axle Rear
3.89
GM6 Axle Rear
4.22
GM7 Axle Rear
3.68
GM8 Axle Rear
2.56
GN9 Axle Rear
4.11
GS1 Axle Rear
2.73
GS3 Axle Rear
3.73
GS4 Axle Rear
3.70
GS5 Axle Rear
4.11
GS6 Axle Rear
4.56
GS8 Axle Rear
3.94
GT1 Axle Rear
2.56
GT2 Axle Rear
2.29
GT4 Axle Rear (DUP WITH 5 X 1)
3.73
GT5 Axle Rear (DUP WITH GT8)
4.10
GT7 Axle Rear
3.33
GT8 Axle Rear (DUP WITH GT5)
4.10
GU1 Axle Rear
2.41
GU2 Axle Rear
2.73
GU3 Axle Rear 2.93
GU4 Axle Rear
3.08
GU5 Axle Rear
3.23
GU6 Axle Rear
3.42
GU7 Axle Rear
2.77
GU8 Axle Rear
3.90
GU9 Axle Rear
3.91
GV0 Axle Rear
3.55
GV1 Axle Rear
2.73
GV2 Axle Rear
5.83
GV3 Axle Rear
3.08
GV4 Axle Rear
3.36
GV5 Axle Rear
3.55
GV7 Axle Rear
4.11
GV8 Axle Rear
2.72
GV9 Axle Rear
4.25
GW2 Axle Rear
2.56
GW3 Axle Rear
2.56
GW4 Axle Rear
3.31
GW5 Axle Rear
2.73
GW6 Axle Rear
3.27
GW8 Axle Rear
4.10
GW9 Axle Rear (DUP WITH GU3)
2.93
GX1 Axle Rear
3.70
GX2 Axle Rear
3.07
GX3 TransAxle Final Drive
3.33
GX4 Axle Rear
3.75
GX5 Axle Rear
4.09
GX6 Axle Rear
3.53
GX8 TransAxle Final Drive
3.74
GY2 Axle Rear
3.31
GY3 TransAxle Final Drive

4.29

GY4 Axle Rear
4.53
GY5 Axle Front
3.65
GY7 TransAxle Final Drive
4.18
GY9 Axle Rear
4.31






Rear Axle Code example: CB G 112 1 E
(CB = Ratio, G = Plant, 112 = 112th day of year, 1 = shift, E = Positraction Source)

Assembly Plant Codes
Buick - B
Buffalo - C
Cadillac - D
Detriot Gear & Axle - G
GM of Canada - K
Warren, MI - W
Oldsmobile - O
Pontiac - P
Pontiac/Canada - M

Shift: D or 1 = Day shift| N or 2 = Night shift

Positraction Source/Code:
- = No positraction
D = Dana Positraction Differential
E = Eaton Positraction Differential
G = Chevrolet G&A Positraction Carrier
O = Oldsmobile Positraction Carrier
W = Warren/Warner Motive

Positraction Casting Numbers
Due to the possible confusion with gear ratio descriptions... a HIGHER number is a LOWER gear.
In the below examples, 2.56:1 & down = 2.41, 2.56, etc... which is actually a HIGHER gear ratio.

8.5" "Corporate"
Casting # Series Gearing
410408N 3 2.73:1 & up
410409N 2 2.56:1 & down

rear axle casting date code Rear Housing Casting Date

Example: D143 - (D = Month, 14 = Day, 1 = Last digit of year (1973)).

Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec

Axle Ratio Stamping codes (First two letters):

1973

2.73..............WA
2.73..............AC
2.73 posi........XB
2.73 Posi........CC
3.08..............WC
3.08..............AD
3.08 Posi........XC
3.08 Posi........CD
3.42..............WE
3.42...............AJ
3.42 Posi.........XE
3.42 Posi.........CJ


1974

2.73..............AC
2.73..............CC
2.73..............WB
2.73 Posi........XA
3.08..............AD
3.08 Posi........CD
3.08..............WC
3.08 Posi........XC
3.42..............AJ
3.42 Posi........CJ
3.42..............WE
3.42 Posi........XE


1975

2.56 posi........CH
2.56..............AH
2.73..............WA
2.73posi........XA
2.73posi........CC
2.73..............AC
3.08..............WC
3.08 posi........XC
3.08 posi........CD
3.08..............AD
3.42..............WE
3.42 posi........XE
3.42 posi........CJ
3.42..............AJ


1976

2.56 POSI........CH
2.56 POSI........AH
2.73...............WA
2.73 POSI........XA
2.73 POSI........CC
2.73...............AC
3.08...............WC
3.08 POSI........XC
3.08 POSI........CD
3.08...............AD


1977

2.56.............AB
2.56 POSI.....CB
2.73.............ZE
2.73.............AC
2.73 POSI.....ZW
2.73 POSI.....CC
3.08.............ZJ
3.08.............AF
3.08 POSI.....ZY
3.08 POSI.....CF



Axle Ratio   Tooth Combination
2.56:1 41,16
2.73:1 41,15
3.07:1 43,14
3.08:1 40,13
3.08:1 37,12
3.31:1 43,13
3.36:1 37,11
3.42:1 41,12
3.55:1 39,11
3.73:1 41,11
4.10:1 41,10
4.11:1 37,9