There are 2 most important kinds of transmissions: automatic and manual. Computerized transmissions use fluid couplings in lieu of a clutch, and they typically have more gears than handbook transmissions. The transmission filter aids to remove Grime and contaminants from the automatic transmission fluid, which serves several reasons, for example: https://filtergearbox18394.mybuzzblog.com/13815840/rumored-buzz-on-filter-gearbox