- Appropriate coefficient of friction for most manual transmission synchronizers (other's synthetic gear oils are often too slippery for proper synchro engagement) - Red Line offers lubricants to pinpoint nearly every transmission application - MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears - Excellent gear and synchro protection, balanced slipperiness for easier shifting in cold climates - Excellent for high- and low-mile transmissions - Compatib le with petroleums and other synthetics - 75W90 GL-4 gear oil (similar to SAE 5W40/10W40 engine oil viscosity) - Popular in Nissan, Mazda, Mitsubishi, VW/Audi, Lotus Elise/Exige, Toyota - Offers quicker shifts, perfect synchronizer coefficient of friction - Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage - High performance gear protection and longer synchro life - Eliminates notchy shifting, even when cold - Satisfies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 40, 10W40, and 15W40 - Recommended for GL-1, GL-3, and GL-4 applications, as well as where most special synchromesh fluids are specified