GM RPO Codes – Factory Identification Labels and Interpretation

GM RPO Codes, or General Motors “Regular Production Option” codes contain lots of valuable information about your GM vehicle. Identify your GMC or Chevrolet rear end gear ratio by the RPO Codes, usually located on the placard labeled “Service Parts Identification” inside the drivers door panel or glove box. (Accurate identification using the GM RPO code assumes that the rear end has not been previously modified) The prefix is usually F, G or H when referring to Axle Identification. The list below is a partial list of typical GM RPO Codes, specifically the codes pertaining to Axle Identification, Differential Type and Gear Ratio.

RPO Code Description Ratio
G11 Transaxle Final Drive 2.56
G44 Axle Rear 3.07
G72 Axle Rear 2.14
G75 Axle Rear 3.62
G76 Positraction Rear
G80 Axle Positraction, Limited Slip
G81 Positraction Rear Axle
G82 Axle Rear 4.56
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G84 Axle Rear 4.10
G86 Axle Rear, Limited Slip
G87 Ring Gear, 8.5″
G89 Ring Gear, 7.5″
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
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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
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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
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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 of 5X1) 3.73
GT5 Axle Rear (Dup of GT8) 4.10
GT7 Axle Rear 3.33
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GT8 Axle Rear (Dup of 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
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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
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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 of GU3) 2.93
GX1 Axle Rear 3.70
GX2 Axle Rear 3.07
GX3 Transaxle Final Drive 3.33
GX4 Axle Rear 3.75
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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
GYS Transaxle Final Drive 3.65
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H01 Axle Rear 3.07
H04 Axle Rear, Single Speed 4.11
H05 Axle Rear 3.73
H12 Axle Rear, 21000 Lbs, Eaton 21065S, Single Speed
H42 Axle Rear 6.17
H43 Axle Rear 5.43
HA3 Axle Rear, Single Speed 5.29
HC4 Axle Rear 4.56
HC7 Axle Rear, 7500 Lbs, Single Speed 2.38
HC8 Axle Rear, Single Speed, Truck 3.21
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HC9 Axle Rear 5.13
HE3 Axle Rear, 3500 Lbs, Single Speed 3.07
HE4 Axle Rear 3.40
HF7 Axle Rear, 10000 Lbs, Dana 70, Single 4.56
HF8 Axle Rear 4.88
HJ1 Axle Rear 4.55
HJ2 Axle Rear 5.86
HJ3 Axle Rear 4.75
HJ4 Axle Rear 6.50
HJ5 Axle Rear 5.57
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HJ6 Axle Rear 4.78
HJ7 Axle Rear 4.88
HK1 Axle Rear 2.87
HK3 Axle Rear 6.14
HK9 Axle Rear 10000 Lbs, Single Spd 5.86
HO4 Axle Rear 4.11
HO6 Axle Rear 4.63




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