When industry is looking at the best ways to increase efficiency@ reduce downtime and increase profitability@ gearbox performance and reliability are key factors. In most applications gearbox reliability is critical to the productivity of the overall plant operation. Repair is often required with a swift turn around@ as down time is very expensive. Designing for repair@ and writing effective repair procedures@ can speed the service time@ and provide a quality refurbishment. Minimizing down time and extending service life will contribute significantly to achieving the lowest overall operation costs. The best practices listed below are proven@ effective methods used to install and remove bearings@ seals@ gears@ couplings and shafts within a gearbox. These techniques are not new@ and are usually obtained by hard won experience. Collecting them in one location is an attempt to document the best practices and provide a reference for design engineers. Engineers write the procedures for assembly and disassembly@ they also dictate to the rest of the design team the design intent. Including features to facilitate disassembly@ minimizes repair cycle time and helps to prevent damage to components that could radically compromise their design life or performance.