RPO Codes:
G80 | Axle Positraction, Limited Slip |
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G81 | Positraction Rear Axle |
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G82 | Axle Rear |
4.56
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G84 | Axle Rear |
4.10
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G86 | Axle , Rear, Limited Slip |
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G87 | Ring Gear, 8.50 Inch |
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G89 | Ring Gear, 7.50 Inch |
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G90 | Rear |
3.15
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G91 | Special Highway Rear Axle |
3.08
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G94 | Axle Rear |
3.31
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G96 | Axle Rear |
3.55
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G97 | Axle Rear |
2.73
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GH0 | Axle Rear |
3.54
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GH2 | Axle Rear |
2.29
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GH3 | Axle Rear |
2.77
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GH4 | Axle Rear |
2.92
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GH7 | Axle Rear |
2.73
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GJ1 | Axle Rear |
5.38
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GJ2 | Axle Rear |
5.13
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GK7 | Axle Rear |
4.78
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GK8 | Axle Rear |
4.33
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GK9 | Axle Rear |
4.63
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GL0 | Axle Rear |
5.13
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GL3 | Axle Rear |
6.17
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GM1 | Axle Rear |
2.59
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GM2 | Axle Rear |
3.44
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GM3 | Axle Rear |
3.45
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GM4 | Axle Rear |
3.67
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GM5 | Axle Rear |
3.89
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GM6 | Axle Rear |
4.22
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GM7 | Axle Rear |
3.68
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GM8 | Axle Rear |
2.56
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GN9 | Axle Rear |
4.11
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GS1 | Axle Rear |
2.73
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GS3 | Axle Rear |
3.73
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GS4 | Axle Rear |
3.70
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GS5 | Axle Rear |
4.11
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GS6 | Axle Rear |
4.56
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GS8 | Axle Rear |
3.94
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GT1 | Axle Rear |
2.56
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GT2 | Axle Rear |
2.29
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GT4 | Axle Rear (DUP WITH 5 X 1) |
3.73
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GT5 | Axle Rear (DUP WITH GT8) |
4.10
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GT7 | Axle Rear |
3.33
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GT8 | Axle Rear (DUP WITH GT5) |
4.10
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GU1 | Axle Rear |
2.41
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GU2 | Axle Rear |
2.73
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GU3 | Axle Rear | 2.93 | ||
GU4 | Axle Rear |
3.08
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GU5 | Axle Rear |
3.23
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GU6 | Axle Rear |
3.42
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GU7 | Axle Rear |
2.77
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GU8 | Axle Rear |
3.90
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GU9 | Axle Rear |
3.91
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GV0 | Axle Rear |
3.55
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GV1 | Axle Rear |
2.73
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GV2 | Axle Rear |
5.83
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GV3 | Axle Rear |
3.08
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GV4 | Axle Rear |
3.36
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GV5 | Axle Rear |
3.55
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GV7 | Axle Rear |
4.11
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GV8 | Axle Rear |
2.72
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GV9 | Axle Rear |
4.25
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GW2 | Axle Rear |
2.56
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GW3 | Axle Rear |
2.56
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GW4 | Axle Rear |
3.31
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GW5 | Axle Rear |
2.73
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GW6 | Axle Rear |
3.27
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GW8 | Axle Rear |
4.10
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GW9 | Axle Rear (DUP WITH GU3) |
2.93
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GX1 | Axle Rear |
3.70
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GX2 | Axle Rear |
3.07
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GX3 | TransAxle Final Drive |
3.33
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GX4 | Axle Rear |
3.75
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GX5 | Axle Rear |
4.09
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GX6 | Axle Rear |
3.53
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GX8 | TransAxle Final Drive |
3.74
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GY2 | Axle Rear |
3.31
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GY3 | TransAxle Final Drive |
4.29 |
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GY4 | Axle Rear |
4.53
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GY5 | Axle Front |
3.65
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GY7 | TransAxle Final Drive |
4.18
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GY9 | Axle Rear |
4.31
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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 |
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