Additional training may be necessary for mechanics who wish to specialize in diesel equipment. For entry jobs, employers generally look for applicants who have mechanical aptitude and are at least 18 years of age and in good physical condition. Completion of high school also is desirable. Good reading skills are needed to study complex service instruction manuals. A State chauffeur's license is needed for test driving trucks or buses on public roads.
Many employers prefer graduates of formal training programs in diesel mechanics.
They provide a foundation in the basics of the latest diesel technology, such as the use of electronics, and speed advancement to the journey-man mechanic level. A formal 4-year apprenticeship is another good way to learn diesel mechanics. While never plentiful, apprenticeships are becoming rare because employers are reluctant to make such a long-term investment in training, especially when graduates of postsecondary diesel mechanic programs are increasing in number. Typical apprenticeship programs for diesel truck and bus mechanics consist of approximately 8,000 hours of practical experience working on transmission, engines, and other components and at least 576 hours of formal instruction to learn blueprint reading, mathematics, engine theory, and safety. Frequently, these programs include training in both diesel and gasoline engine repair.