Manual transmissions Archives - Transmission Digest
Simple Issues Turn into Nasty Problems

The same goes for manual transmissions, as the OEM will specify a fluid to match the friction coefficient of the synchronizer material. Brass or bronze rings have faded away in most late-model stick transmissions, replaced by sintered metal, paper or carbon-fiber linings, or hybrid combinations of any of the types of linings. Using an oil other than the one specified will create notchy, dragging or blocked-out shifts. This is also true for the axle assemblies, as more of these units are using limited-slip differentials to provide power to both drive wheels. Incorrect lubricants or additives will cause clutch chatter on turns and shorten the life of the friction material because of overheating from slippage.