Decoding Regular Production Option codes found in GM Vehicles
GM RPO CODES
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.
GM RPO Codes:
Ring and Pinion Repair and GM RPO Codes chart.
GM RPO Codes |
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| RPO Code | Description | Ratio | ||
| F16 | Transaxle Final Drive | 2.53 | ||
| F17 | Transaxle Final Drive | 2.84 | ||
| F18 | Transaxle Final Drive | 2.65 | ||
| F25 | Transaxle Final Drive | 3.32 | ||
| F29 | Transaxle Final Drive | 2.82 | ||
| F36 | Axle Front | 2.19 | ||
| F45 | Axle Front | 2.93 | ||
| F47 | Axle Front | 2.73 | ||
| F57 | Axle Front | 3.15 | ||
| F62 | Transaxle Final Drive | 2.39 | ||
| F67 | Transaxle Final Drive | 3.19 | ||
| F68 | Transaxle Final Drive | 3.45 | ||
| F75 | Transaxle Final Drive | 3.18 | ||
| F77 | Transaxle Final Drive | 3.73 | ||
| F79 | Transaxle Final Drive | 2.97 | ||
| F82 | Transaxle Final Drive | 3.23 | ||
| F83 | Transaxle Final Drive | 3.05 | ||
| F90 | Axle Front | 2.73 | ||
| FA0 | Rear | 5.77 | ||
| FA1 | Rear 2 Speed | 4.88/6.94 | ||
| FA2 | Rear 2 Speed | 4.88/6.94 | ||
| FH5 | Transaxle Final Drive | 2.81 | ||
| FH6 | Axle Front | 3.64 | ||
| FH7 | Transaxle Final Drive | 4.12 | ||
| FH8 | Axle Front | 2.40 | ||
| FH9 | Transaxle Final Drive | 2.60 | ||
| FJ1 | Axle Front | 4.18 | ||
| FJ2 | Axle Front | 3.74 | ||
| FJ3 | Transaxle Final Drive | 3.35 | ||
| FJ4 | Axle Front | 4.53 | ||
| FJ5 | Axle Front | 4.19 | ||
| FJ7 | Axle Front | 4.56 | ||
| FP0 | Transaxle Final Drive | 2.55 | ||
| FP1 | Transaxle Final Drive | 2.72 | ||
| FP2 | Transaxle Final Drive | 3.58 | ||
| FP3 | Transaxle Final Drive | 2.73 | ||
| FP4 | Transaxle Final Drive | 2.69 | ||
| FP5 | Transaxle Final Drive | 2.95 | ||
| FP6 | Transaxle Final Drive | 3.54 | ||
| FP7 | Transaxle Final Drive | 3.73 | ||
| FP8 | Transaxle Final Drive | 3.54 | ||
| FP9 | Transaxle Final Drive | 3.54 | ||
| FQ2 | Transaxle Final Drive | 3.48 | ||
| FQ3 | Transaxle Final Drive | 2.86 | ||
| FQ4 | Transaxle Final Drive | 3.57 | ||
| FQ6 | Transaxle Final Drive | 4.12 | ||
| FQ8 | Transaxle Final Drive | 2.96 | ||
| FQ9 | Transaxle Final Drive | 3.21 | ||
| FR2 | Transaxle Final Drive | 2.93 | ||
| FR3 | Transaxle Final Drive | 3.69 | ||
| FR6 | Transaxle Final Drive | 3.84 | ||
| FR7 | Transaxle Final Drive | 3.95 | ||
| FR8 | Axle Front | 4.17 | ||
| FR9 | Transaxle Final Drive | 3.29 | ||
| FV0 | Transaxle Final Drive | 3.67 | ||
| FV1 | Transaxle Final Drive | 3.72 | ||
| FV2 | Transaxle Final Drive | 4.18 | ||
| FV3 | Transaxle Final Drive | 3.11 | ||
| FV4 | Transaxle Final Drive | 3.71 | ||
| FV5 | Transaxle Final Drive | 4.19 | ||
| FV6 | Transaxle Final Drive | 4.24 | ||
| FV7 | Transaxle Final Drive | 4.29 | ||
| FV8 | Transaxle Final Drive | 4.31 | ||
| FV9 | Transaxle Final Drive | 4.53 | ||
| FVO | Transaxle Final Drive | 3.67 | ||
| FW2 | Transaxle Final Drive | 3.06 | ||
| FW3 | Transaxle Final Drive | 4.02 | ||
| FW4 | Transaxle Final Drive | 3.89 | ||
| FW5 | Transaxle Final Drive | 4.10 | ||
| FW6 | Transaxle Final Drive | 3.42 | ||
| FW7 | Transaxle Final Drive | 3.83 | ||
| FW8 | Transaxle Final Drive | 4.28 | ||
| FW9 | Transaxle Final Drive | 3.43 | ||
| FWS | Transaxle Final Drive | 4.10 | ||
| FX1 | Transaxle Final Drive | 3.94 | ||
| FX2 | Transaxle Final Drive | 2.66 | ||
| FX4 | Transaxle Final Drive | 3.35 | ||
| FX8 | Transaxle Final Drive | 3.61 | ||
| FY1 | Transaxle Final Drive | 2.36 | ||
| FY3 | Transaxle Final Drive | 3.79 | ||
| FY5 | Transaxle Final Drive | 3.52 | ||
| 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 | Not Open Diff – Positraction / Limited Slip / Typ. Gov-Lock | |||
| G81 | Positraction Rear Axle | |||
| G82 | Axle Rear | 4.56 | ||
| 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 | ||
| 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 of 5X1) | 3.73 | ||
| GT5 | Axle Rear (Dup of GT8) | 4.10 | ||
| GT7 | Axle Rear | 3.33 | ||
| 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 | ||
| 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 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 | ||
| 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 | ||
| 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 | ||
| 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 | ||
| 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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