Manual transmissions or gearboxes, like automatic transmissions, are the vehicle’s main component which distributes the power created by it’s engine to the wheels. Both applications control that engine power and deliver it to the wheels in order to produce a desired speed, but each does it in very different ways. In the manual transmission, the driver controls the engagement of gears for each shift with the movement of a clutch. The clutch allows the engine’s flywheel to separate from the manual transmission in order for it’s gears, often moving at different speeds, to slow down, coast, and then re-engage at the correct time. This allows a smooth engagement of gears at a different ratio in order to move to a different speed. Oil for manual transmissions act as the lubricant for this engagement.
The engagement of gears when shifting a manual transmission incorrectly can cause a terrible noise of metal on metal grinding. This noise is caused by the metal gears not engaging at the same speed. This often happens with inexperienced users, leaving metal debris in the fluid, eventually causing even more harm to those gears in the future. Even with experienced drivers, the gears in a manual transmission wear over time because they are not always perfectly engaged each and every time it is shifted. The oil for manual transmissions must be a very specific composition and viscosity in order to handle such wear.
With this propensity to wear over time, the oil used in a manual transmission, much like the oil in a differential, must be a specific thickness and viscosity. Because synthetic manual transmission or differential oil is scientifically designed for uniformity and more specific purposes, it tends to be better than conventional oils for this application. Conventional oils are refined from crude oil and are unstable and often full of byproducts that slip through in the process. Synthetic manual transmission oil is chemically engineered to have a uniform molecular structure. This allows it to flow in the gearbox more smoothly and creates an easier engagement of gears on each shift over time. This smoother shifting will lengthen the life of the manual transmission and also increase the fuel economy of the engine in that vehicle.
Another benefit of synthetic fluids are that they last longer and are less subject to thermal breakdown over time. With oils for manual transmissions being changed at longer intervals than their counterparts, synthetic manual transmission or differential oil will hold up to the stresses of gear engagement and high temperatures created by this friction longer than conventional, petroleum based fluids.
For over 25 years Vincent Peter Platania,Jr has been marketing, consulting and formulating high performance lubricants.
Source for AMSOIL, the World’s Best Synthetic Lubricants, Motor Oils and Filters.