They usually repair or adjust a part that is not working properly. Parts that cannot be fixed are replaced. In many shops, mechanics do all kinds of repairs, working on a vehicle's electrical system one day and doing major engine repairs the next. In some large shops, mechanics specialize in one or two types of work. For example, one mechanic may specialize in major engine repair, another in transmission work, another in electrical systems, and yet another in suspension or brake systems.
Diesel mechanics use a variety of tools in their work.
For heavy work, such as removing engines and transmissions, two mechanics may work as a team, or a mechanic may be assisted by an apprentice or helper. Mechanics generally get their assignments from shop supervisors or service managers, who may check the mechanics' work or assist in diagnosing problems. Diesel mechanics spend much time doing preventive maintenance to assure safety and to reduce breakdowns. Working Conditions Diesel mechanics usually work indoors, although they may occasionally make repairs on the road. They are subject to the usual shop hazards such as cuts and bruises.