Which type of fluid is typically used in a manual transmission?

Manual transmissions typically use gear oil or manual transmission fluid (MTF) because these fluids are specifically designed to lubricate the gears and bearings within the transmission, providing the necessary protection against wear and ensuring smooth shifting. Gear oils have additives that improve their performance under high pressure, which is essential for the operational demands of a manual gearbox.

In contrast, engine oil is formulated for internal combustion engines and lacks the specific additives required for the higher pressure and different operating conditions found in a manual transmission. Brake fluid is designed for hydraulic braking systems and is not suitable for lubrication purposes. Power steering fluid is also specialized for hydraulic applications and does not have the properties necessary to function effectively in a manual transmission. Therefore, gear oil or manual transmission fluid is the correct choice for maintaining the performance and longevity of manual transmissions.