As modern cars grow increasingly complex and have to meet harsher demands, so too are the demands placed on oils. Engine oils are often superseded by new and improved substitutions, so finding something suitable for your aging classic is never an issue. The same can not always be said about gear and transmission oils, as the complex nature of the internals dictates what oils can be used. A common specification for gear oils are the API GL index, where a number typically identifies the use of extreme pressure additives.

This does not always mean the higher number is better! Any car requiring a GL-4 oil can not use a GL-5 oil, as the higher sulphur content of the additive pack causes accelerated wear on any yellow metals, typically brass and bronze components. For popular transmission from your 80’s or 90’s car, this can be synchro rings or selector forks, which can drastically affect the drivability of your car. Premature wear here can be devastating, increasing the difficulty of getting into gears – or even selecting them outright. Once these components are degraded, the only fix is replacement of the affected parts, which means removal and complete disassembly of the whole transmission.

Amsoil Manual Transmission & Transaxle 75W-90 Manual Transmission Oil MTG

Amsoil have specifically developed a gear oil to meet GL-4 specifications, separate to the Severe Gear range of oils. Amsoil MTG is a 75W-90 formulation that provides superior protection under harsh conditions. Towing, rough terrain, or even just high power applications – MTG resists thermal breakdown and mechanical shearing, giving long service life.

Amsoil MTG is available here in both quart bottle and easy packs.