GM RPO Axle Codes
To find the axle gear ratio of any GM vehicle, locate the RPO sticker (typically located in the glove box) and write down any codes starting with F, G, or H. Then, find those codes in the table below.
GM RPO Axle Code Notes
These RPO codes are used to idicate a specific type of differential and/or ring gear size. Not all applications will have one of these codes but when they apply, they will be listed in addition to an axle code found in the main RPO axle code list below.
| RPO | Axle Type |
| G76 | Rear Axle (Posi) |
| G80 | Positraction |
| G81 | Positraction (Rear) |
| G86 | Limited Slip (Rear) |
| G87 | 8.5" Ring Gear |
| G89 | 7.5" Ring Gear |
GM RPO Axle Code List (F)
The following is a complete list of GM RPO axle codes for Chevy and GMC vehicles starting with the letter F.
| RPO | Axle Type | Ratio |
| F16 | Transaxle | 2.53 |
| F17 | Transaxle | 2.84 |
| F18 | Transaxle | 2.65 |
| F25 | Transaxle | 3.32 |
| F29 | Transaxle | 2.82 |
| F36 | Front Axle | 2.19 |
| F45 | Front Axle | 2.93 |
| F47 | Front Axle | 2.73 |
| F57 | Front Axle | 3.15 |
| F62 | Transaxle | 2.39 |
| F67 | Transaxle | 3.19 |
| F68 | Transaxle | 3.45 |
| F75 | Transaxle | 3.18 |
| F77 | Transaxle | 3.73 |
| F79 | Transaxle | 2.97 |
| F82 | Transaxle | 3.23 |
| F83 | Transaxle | 3.05 |
| F90 | Front Axle | 2.73 |
| FA0 | Rear Axle | 5.77 |
| FA1 | Rear Axle (2 Speed) | 4.88/6.94 |
| FA2 | Rear Axle (2 Speed) | 4.88/6.94 |
| FH5 | Transaxle | 2.81 |
| FH6 | Front Axle | 3.64 |
| FH7 | Transaxle | 4.12 |
| FH8 | Front Axle | 2.40 |
| FH9 | Transaxle | 2.60 |
| FJ1 | Front Axle | 4.18 |
| FJ2 | Front Axle | 3.74 |
| FJ3 | Transaxle | 3.35 |
| FJ4 | Front Axle | 4.53 |
| FJ5 | Front Axle | 4.19 |
| FJ7 | Front Axle | 4.56 |
| FP0 | Transaxle | 2.55 |
| FP1 | Transaxle | 2.72 |
| FP2 | Transaxle | 3.58 |
| FP3 | Transaxle | 2.73 |
| FP4 | Transaxle | 2.69 |
| FP5 | Transaxle | 2.95 |
| FP6 | Transaxle | 3.54 |
| FP7 | Transaxle | 3.73 |
| FP8 | Transaxle | 3.54 |
| FP9 | Transaxle | 3.54 |
| FQ2 | Transaxle | 3.48 |
| FQ3 | Transaxle | 2.86 |
| FQ4 | Transaxle | 3.57 |
| FQ6 | Transaxle | 4.12 |
| FQ8 | Transaxle | 2.96 |
| FQ9 | Transaxle | 3.21 |
| FR2 | Transaxle | 2.93 |
| FR3 | Transaxle | 3.69 |
| FR6 | Transaxle | 3.84 |
| FR7 | Transaxle | 3.95 |
| FR8 | Front Axle | 4.17 |
| FR9 | Transaxle | 3.29 |
| FV0 | Transaxle | 3.67 |
| FV1 | Transaxle | 3.72 |
| FV2 | Transaxle | 4.18 |
| FV3 | Transaxle | 3.11 |
| FV4 | Transaxle | 3.71 |
| FV5 | Transaxle | 4.19 |
| FV6 | Transaxle | 4.24 |
| FV7 | Transaxle | 4.29 |
| FV8 | Transaxle | 4.31 |
| FV9 | Transaxle | 4.53 |
| FVO | Transaxle | 3.67 |
| FW2 | Transaxle | 3.06 |
| FW3 | Transaxle | 4.02 |
| FW4 | Transaxle | 3.89 |
| FW5 | Transaxle | 4.10 |
| FW6 | Transaxle | 3.42 |
| FW7 | Transaxle | 3.83 |
| FW8 | Transaxle | 4.28 |
| FW9 | Transaxle | 3.43 |
| FWS | Transaxle | 4.10 |
| FX1 | Transaxle | 3.94 |
| FX2 | Transaxle | 2.66 |
| FX4 | Transaxle | 3.35 |
| FX8 | Transaxle | 3.61 |
| FY1 | Transaxle | 2.36 |
| FY3 | Transaxle | 3.79 |
| FY5 | Transaxle | 3.52 |
GM RPO Axle Code List (G)
The following is a complete list of GM RPO axle codes for Chevy and GMC vehicles starting with the letter G.
| RPO | Axle Type | Ratio |
| G11 | Transaxle | 2.56 |
| G44 | Rear Axle | 3.07 |
| G72 | Rear Axle | 2.14 |
| G75 | Rear Axle | 3.62 |
| G82 | Rear Axle | 4.56 |
| G84 | Rear Axle | 4.10 |
| G90 | Rear Axle | 3.15 |
| G91 | Rear Axle (HWY) | 3.08 |
| G94 | Rear Axle | 3.31 |
| G96 | Rear Axle | 3.55 |
| G97 | Rear Axle | 2.73 |
| GH0 | Rear Axle | 3.54 |
| GH2 | Rear Axle | 2.29 |
| GH3 | Rear Axle | 2.77 |
| GH4 | Rear Axle | 2.92 |
| GH7 | Rear Axle | 2.73 |
| GJ1 | Rear Axle | 5.38 |
| GJ2 | Rear Axle | 5.13 |
| GK7 | Rear Axle | 4.78 |
| GK8 | Rear Axle | 4.33 |
| GK9 | Rear Axle | 4.63 |
| GL0 | Rear Axle | 5.13 |
| GL3 | Rear Axle | 6.17 |
| GM1 | Rear Axle | 2.59 |
| GM2 | Rear Axle | 3.44 |
| GM3 | Rear Axle | 3.45 |
| GM4 | Rear Axle | 3.67 |
| GM5 | Rear Axle | 3.89 |
| GM6 | Rear Axle | 4.22 |
| GM7 | Rear Axle | 3.68 |
| GM8 | Rear Axle | 2.56 |
| GN9 | Rear Axle | 4.11 |
| GS1 | Rear Axle | 2.73 |
| GS3 | Rear Axle | 3.73 |
| GS4 | Rear Axle | 3.70 |
| GS5 | Rear Axle | 4.11 |
| GS6 | Rear Axle | 4.56 |
| GS8 | Rear Axle | 3.94 |
| GT1 | Rear Axle | 2.56 |
| GT2 | Rear Axle | 2.29 |
| GT4 | Rear Axle (5X1) | 3.73 |
| GT5 | Rear Axle (GT8) | 4.10 |
| GT7 | Rear Axle | 3.33 |
| GT8 | Rear Axle (GT5) | 4.10 |
| GU1 | Rear Axle | 2.41 |
| GU2 | Rear Axle | 2.73 |
| GU3 | Rear Axle | 2.93 |
| GU4 | Rear Axle | 3.08 |
| GU5 | Rear Axle | 3.23 |
| GU6 | Rear Axle | 3.42 |
| GU7 | Rear Axle | 2.77 |
| GU8 | Rear Axle | 3.90 |
| GU9 | Rear Axle | 3.91 |
| GV0 | Rear Axle | 3.55 |
| GV1 | Rear Axle | 2.73 |
| GV2 | Rear Axle | 5.83 |
| GV3 | Rear Axle | 3.08 |
| GV4 | Rear Axle | 3.36 |
| GV5 | Rear Axle | 3.55 |
| GV7 | Rear Axle | 4.11 |
| GV8 | Rear Axle | 2.72 |
| GV9 | Rear Axle | 4.25 |
| GW2 | Rear Axle | 2.56 |
| GW3 | Rear Axle | 2.56 |
| GW4 | Rear Axle | 3.31 |
| GW5 | Rear Axle | 2.73 |
| GW6 | Rear Axle | 3.27 |
| GW8 | Rear Axle | 4.10 |
| GW9 | Rear Axle (GU3) | 2.93 |
| GX1 | Rear Axle | 3.70 |
| GX2 | Rear Axle | 3.07 |
| GX3 | Transaxle | 3.33 |
| GX4 | Rear Axle | 3.75 |
| GX5 | Rear Axle | 4.09 |
| GX6 | Rear Axle | 3.53 |
| GX8 | Transaxle | 3.74 |
| GY2 | Rear Axle | 3.31 |
| GY3 | Transaxle | 4.29 |
| GY4 | Rear Axle | 4.53 |
| GY5 | Front Axle | 3.65 |
| GY7 | Transaxle | 4.18 |
| GY9 | Rear Axle | 4.31 |
| GYS | Transaxle | 3.65 |
GM RPO Axle Code List (H)
The following is a complete list of GM RPO axle codes for Chevy and GMC vehicles starting with the letter H.
| RPO | Axle Type | Ratio |
| H01 | Rear Axle | 3.07 |
| H04 | Rear Axle | 4.11 |
| H05 | Rear Axle | 3.73 |
| H12 | Rear Axle (Eaton 21065S) | -- |
| H42 | Rear Axle | 6.17 |
| H43 | Rear Axle | 5.43 |
| HA3 | Rear Axle | 5.29 |
| HC4 | Rear Axle | 4.56 |
| HC7 | Rear Axle (7,500 Lbs.) | 2.38 |
| HC8 | Rear Axle (Truck) | 3.21 |
| HC9 | Rear Axle | 5.13 |
| HE3 | Rear Axle (3,500 Lbs.) | 3.07 |
| HE4 | Rear Axle | 3.40 |
| HF7 | Rear Axle, (Dana 70) | 4.56 |
| HF8 | Rear Axle | 4.88 |
| HJ1 | Rear Axle | 4.55 |
| HJ2 | Rear Axle | 5.86 |
| HJ3 | Rear Axle | 4.75 |
| HJ4 | Rear Axle | 6.50 |
| HJ5 | Rear Axle | 5.57 |
| HJ6 | Rear Axle | 4.78 |
| HJ7 | Rear Axle | 4.88 |
| HK1 | Rear Axle | 2.87 |
| HK3 | Rear Axle | 6.14 |
| HK9 | Rear Axle (10,000 Lbs.) | 5.86 |
| HO4 | Rear Axle | 4.11 |
| HO6 | Rear Axle | 4.63 |
This GM RPO axle code guide is ©Copyright Crawlpedia.com - Please provide a link back to this page when copying.
Data is accurate to the best of our knowledge and is offered as-is with no guarantee.
More Gear and Axle Guides:
Dana 60 Axle BOM Guide - A complete reference guide to Dana 60 axle Bill of Materials codes.
Differential Locker Comparison - A detailed comparison of popular differentials and lockers.
Gear Ratio Finder - Find the ideal axle gear ratio for your new larger or smaller tires.
Gear Ratio Calculator - Calculate the gear ratio of gears based on their tooth count.
Ring and Pinion Setup Specs - Ring and pinion gear setup specifications for popular axles.
Ring and Pinion Ratio Variations - An explanation of why some ring and pinion gear ratios vary.
Thick Gears and Carrier Breaks - Thick ring and pinion gears and differential carrier breaks explained.
