| Gearbox Ratios | ||||||||||
| All 77-82 | G28.05 | G28.03 | ||||||||
| Gear | Ratio | Layshaft | Output | Shift Ratio | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.3913 | 3.600963 | 7.922118 | 8.161942 | 9.493218 | 9.820545 | 9.902647 | 11.12697 | |
| 2 | 1.7727 | 1.3913 | 2.466358 | 0.684916 | 5.425987 | 5.590246 | 6.502058 | 6.72625 | 6.782483 | 7.621045 |
| 3 | 1.3077 | 1.3913 | 1.819403 | 0.737688 | 4.002687 | 4.123859 | 4.796492 | 4.961876 | 5.003358 | 5.621955 |
| 4 | 0.9655 | 1.3913 | 1.3433 | 0.738319 | 2.95526 | 3.044724 | 3.541342 | 3.663448 | 3.694075 | 4.150797 |
| 5 | 1 | 1 | 1 | 0.744435 | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| Euro 83+ and US 89+ | G28.12 | G28.07/10/55 | ||||||||
| Gear | Ratio | Layshaft | Output | Shift Ratio | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4545 | 3.764537 | 8.281981 | 8.532699 | 9.924449 | 10.26665 | 10.35248 | 11.63242 | |
| 2 | 1.7272 | 1.4545 | 2.512212 | 0.667336 | 5.526867 | 5.694181 | 6.622946 | 6.851306 | 6.908584 | 7.762736 |
| 3 | 1.2307 | 1.4545 | 1.790053 | 0.712541 | 3.938117 | 4.057334 | 4.719117 | 4.881833 | 4.922646 | 5.531264 |
| 4 | 0.931 | 1.4545 | 1.35414 | 0.75648 | 2.979107 | 3.069293 | 3.569918 | 3.693009 | 3.723884 | 4.184291 |
| 5 | 1 | 1 | 1 | 0.738476 | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| US 83-84 | G28.08 | |||||||||
| Gear | Ratio | Layshaft | Output | Shift Ratio | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.65 | 4.27053 | 9.395166 | 9.679583 | 11.2584 | 11.64659 | 11.74396 | 13.19594 | |
| 2 | 1.7272 | 1.65 | 2.84988 | 0.667336 | 6.269736 | 6.459538 | 7.513139 | 7.772193 | 7.83717 | 8.806129 |
| 3 | 1.2307 | 1.65 | 2.030655 | 0.712541 | 4.467441 | 4.602683 | 5.353416 | 5.538002 | 5.584301 | 6.274724 |
| 4 | 0.931 | 1.65 | 1.53615 | 0.75648 | 3.37953 | 3.481838 | 4.049752 | 4.189388 | 4.224413 | 4.746704 |
| 5 | 1 | 1 | 1 | 0.650978 | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| US 85-88 | G28.11/13 | |||||||||
| Gear | Ratio | Layshaft | Output | Shift Ratio | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.5714 | 4.067097 | 8.947614 | 9.218483 | 10.72209 | 11.09179 | 11.18452 | 12.56733 | |
| 2 | 1.7272 | 1.5714 | 2.714122 | 0.667336 | 5.971069 | 6.151829 | 7.15524 | 7.401954 | 7.463836 | 8.386637 |
| 3 | 1.2307 | 1.5714 | 1.933922 | 0.712541 | 4.254628 | 4.383428 | 5.098399 | 5.274192 | 5.318285 | 5.975819 |
| 4 | 0.931 | 1.5714 | 1.462973 | 0.75648 | 3.218541 | 3.315976 | 3.856837 | 3.989821 | 4.023177 | 4.520588 |
| 5 | 1 | 1 | 1 | 0.683539 | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| All 92+ | G28.57 | |||||||||
| Gear | Ratio | Layshaft | Output | Shift Ratio | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4583 | 3.774372 | 8.303619 | 8.554992 | 9.950377 | 10.29347 | 10.37952 | 11.66281 | |
| 2 | 1.7272 | 1.4583 | 2.518776 | 0.667336 | 5.541307 | 5.709057 | 6.640249 | 6.869205 | 6.926633 | 7.783017 |
| 3 | 1.2307 | 1.4583 | 1.79473 | 0.712541 | 3.948406 | 4.067935 | 4.731446 | 4.894587 | 4.935507 | 5.545715 |
| 4 | 0.931 | 1.4583 | 1.357677 | 0.75648 | 2.98689 | 3.077311 | 3.579245 | 3.702658 | 3.733613 | 4.195223 |
| 5 | 1 | 1 | 1 | 0.736552 | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| Max Speed at 6000rpms with 25" tire | 446.2486 | |||||||||
| All 77-82 | G28.05 | G28.03 | ||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.3913 | 3.600963 | 0 | 56.32946 | 54.67432 | 47.0071 | 45.44031 | 45.06357 | 40.10512 |
| 2 | 1.7727 | 1.3913 | 2.466358 | 1890.503 | 82.24285 | 79.82629 | 68.6319 | 66.34434 | 65.79428 | 58.55478 |
| 3 | 1.3077 | 1.3913 | 1.819403 | 1573.87 | 111.4873 | 108.2114 | 93.03645 | 89.93546 | 89.18982 | 79.37605 |
| 4 | 0.9655 | 1.3913 | 1.3433 | 1570.085 | 151.0015 | 146.5645 | 126.0111 | 121.8111 | 120.8012 | 107.5091 |
| 5 | 1 | 1 | 1 | 1533.388 | 202.8403 | 196.8802 | 169.2708 | 163.6289 | 162.2722 | 144.417 |
| Euro 83+ and US 89+ | G28.12 | G28.07/10/55 | ||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4545 | 3.764537 | 0 | 53.88187 | 52.29864 | 44.96457 | 43.46586 | 43.10549 | 38.36249 |
| 2 | 1.7272 | 1.4545 | 2.512212 | 1995.982 | 80.74169 | 78.36924 | 67.37917 | 65.13337 | 64.59335 | 57.48599 |
| 3 | 1.2307 | 1.4545 | 1.790053 | 1724.757 | 113.3152 | 109.9857 | 94.56188 | 91.41005 | 90.65218 | 80.67751 |
| 4 | 0.931 | 1.4545 | 1.35414 | 1461.12 | 149.7927 | 145.3914 | 125.0025 | 120.836 | 119.8342 | 106.6486 |
| 5 | 1 | 1 | 1 | 1569.142 | 202.8403 | 196.8802 | 169.2708 | 163.6289 | 162.2722 | 144.417 |
| US 83-84 | G28.08 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.65 | 4.27053 | 0 | 47.49768 | 46.10205 | 39.63695 | 38.31582 | 37.99815 | 33.81712 |
| 2 | 1.7272 | 1.65 | 2.84988 | 1995.982 | 71.17502 | 69.08367 | 59.39576 | 57.41605 | 56.94002 | 50.67477 |
| 3 | 1.2307 | 1.65 | 2.030655 | 1724.757 | 99.88909 | 96.95402 | 83.35773 | 80.57935 | 79.91127 | 71.11844 |
| 4 | 0.931 | 1.65 | 1.53615 | 1461.12 | 132.0446 | 128.1647 | 110.1916 | 106.5188 | 105.6357 | 94.01232 |
| 5 | 1 | 1 | 1 | 2094.131 | 202.8403 | 196.8802 | 169.2708 | 163.6289 | 162.2722 | 144.417 |
| US 85-88 | G28.11/13 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.5714 | 4.067097 | 0 | 49.87347 | 48.40803 | 41.61956 | 40.23234 | 39.89878 | 35.50862 |
| 2 | 1.7272 | 1.5714 | 2.714122 | 1995.982 | 74.73513 | 72.53917 | 62.36668 | 60.28795 | 59.78811 | 53.20948 |
| 3 | 1.2307 | 1.5714 | 1.933922 | 1724.757 | 104.8854 | 101.8036 | 87.52721 | 84.60985 | 83.90836 | 74.67572 |
| 4 | 0.931 | 1.5714 | 1.462973 | 1461.12 | 138.6493 | 134.5754 | 115.7033 | 111.8468 | 110.9195 | 98.71473 |
| 5 | 1 | 1 | 1 | 1898.763 | 202.8403 | 196.8802 | 169.2708 | 163.6289 | 162.2722 | 144.417 |
| All 92+ | G28.57 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4583 | 3.774372 | 0 | 53.74146 | 52.16236 | 44.84741 | 43.3526 | 42.99317 | 38.26253 |
| 2 | 1.7272 | 1.4583 | 2.518776 | 1995.982 | 80.53129 | 78.16503 | 67.2036 | 64.96364 | 64.42504 | 57.3362 |
| 3 | 1.2307 | 1.4583 | 1.79473 | 1724.757 | 113.0199 | 109.6991 | 94.31548 | 91.17186 | 90.41596 | 80.46728 |
| 4 | 0.931 | 1.4583 | 1.357677 | 1461.12 | 149.4024 | 145.0125 | 124.6768 | 120.5212 | 119.5219 | 106.3707 |
| 5 | 1 | 1 | 1 | 1580.688 | 202.8403 | 196.8802 | 169.2708 | 163.6289 | 162.2722 | 144.417 |
| Max Speed at 7000rpms with 25" tire | 520.6233 | |||||||||
| All 77-82 | G28.05 | G28.03 | ||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.3913 | 3.600963 | 0 | 65.71769 | 63.78669 | 54.8416 | 53.01369 | 52.57415 | 46.7893 |
| 2 | 1.7727 | 1.3913 | 2.466358 | 2205.587 | 95.94998 | 93.13066 | 80.07054 | 77.40171 | 76.75998 | 68.3139 |
| 3 | 1.3077 | 1.3913 | 1.819403 | 1836.182 | 130.0685 | 126.2466 | 108.5425 | 104.9247 | 104.0548 | 92.60538 |
| 4 | 0.9655 | 1.3913 | 1.3433 | 1831.766 | 176.1683 | 170.9919 | 147.013 | 142.1129 | 140.9347 | 125.4273 |
| 5 | 1 | 1 | 1 | 1788.953 | 236.647 | 229.6935 | 197.4826 | 190.9003 | 189.3176 | 168.4865 |
| Euro 83+ and US 89+ | G28.12 | G28.07/10/55 | ||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4545 | 3.764537 | 0 | 62.86217 | 61.01508 | 52.45866 | 50.71017 | 50.28974 | 44.75624 |
| 2 | 1.7272 | 1.4545 | 2.512212 | 2328.645 | 94.19863 | 91.43077 | 78.60903 | 75.98892 | 75.3589 | 67.06698 |
| 3 | 1.2307 | 1.4545 | 1.790053 | 2012.216 | 132.2011 | 128.3166 | 110.3222 | 106.645 | 105.7609 | 94.12374 |
| 4 | 0.931 | 1.4545 | 1.35414 | 1704.64 | 174.7582 | 169.6232 | 145.8362 | 140.9754 | 139.8065 | 124.4233 |
| 5 | 1 | 1 | 1 | 1830.666 | 236.647 | 229.6935 | 197.4826 | 190.9003 | 189.3176 | 168.4865 |
| US 83-84 | G28.08 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.65 | 4.27053 | 0 | 55.41395 | 53.78571 | 46.24311 | 44.70178 | 44.33116 | 39.4533 |
| 2 | 1.7272 | 1.65 | 2.84988 | 2328.645 | 83.03752 | 80.59761 | 69.29505 | 66.98538 | 66.43001 | 59.12056 |
| 3 | 1.2307 | 1.65 | 2.030655 | 2012.216 | 116.5373 | 113.113 | 97.25068 | 94.00922 | 93.2298 | 82.97151 |
| 4 | 0.931 | 1.65 | 1.53615 | 1704.64 | 154.052 | 149.5254 | 128.5568 | 124.2719 | 123.2416 | 109.681 |
| 5 | 1 | 1 | 1 | 2443.153 | 236.647 | 229.6935 | 197.4826 | 190.9003 | 189.3176 | 168.4865 |
| US 85-88 | G28.11/13 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.5714 | 4.067097 | 0 | 58.18571 | 56.47603 | 48.55614 | 46.93772 | 46.54857 | 41.42672 |
| 2 | 1.7272 | 1.5714 | 2.714122 | 2328.645 | 87.19098 | 84.62903 | 72.76112 | 70.33593 | 69.75278 | 62.07772 |
| 3 | 1.2307 | 1.5714 | 1.933922 | 2012.216 | 122.3663 | 118.7708 | 102.1151 | 98.71148 | 97.89307 | 87.12167 |
| 4 | 0.931 | 1.5714 | 1.462973 | 1704.64 | 161.7575 | 157.0046 | 134.9871 | 130.4879 | 129.406 | 115.1672 |
| 5 | 1 | 1 | 1 | 2215.224 | 236.647 | 229.6935 | 197.4826 | 190.9003 | 189.3176 | 168.4865 |
| All 92+ | G28.57 | |||||||||
| Gear | Ratio | Layshaft | Output | RPM drop | 2.2 | 2.2666 | 2.6363 | 2.7272 | 2.75 | 3.09 |
| 1 | 2.5882 | 1.4583 | 3.774372 | 0 | 62.69836 | 60.85608 | 52.32197 | 50.57803 | 50.15869 | 44.63961 |
| 2 | 1.7272 | 1.4583 | 2.518776 | 2328.645 | 93.95316 | 91.19252 | 78.40419 | 75.79091 | 75.16253 | 66.89222 |
| 3 | 1.2307 | 1.4583 | 1.79473 | 2012.216 | 131.8566 | 127.9822 | 110.0347 | 106.3672 | 105.4853 | 93.87848 |
| 4 | 0.931 | 1.4583 | 1.357677 | 1704.64 | 174.3028 | 169.1812 | 145.4562 | 140.608 | 139.4422 | 124.0991 |
| 5 | 1 | 1 | 1 | 1844.136 | 236.647 | 229.6935 | 197.4826 | 190.9003 | 189.3176 | 168.4865 |
| G28.03 | 77-80 | All | ||||||||
| G28.05 | 80-81 | All | ||||||||
| G28.07 | 83-84 | S,S2 | Euro/ROW | |||||||
| G28.08 | 83-84 | S | US | |||||||
| G28.09 | 82 | All | ||||||||
| G28.10 | 85-86 | S2,S3 | Euro/ROW | |||||||
| G28.11 | 85-86 | S3 | US | |||||||
| G28.12 | 87-89 | S4 | Euro/ROW | |||||||
| 89 | S4 | US | ||||||||
| G28.13 | 87-88 | S4 | US | |||||||
| G28.55 | 88 | CS/SE | Euro/ROW | |||||||
| 89-91 | GT | All | ||||||||
| G28.57 | 92-95 | GTS | All | |||||||