At least 1-2 years of hands-on diesel mechanic or fleet maintenance experience working on commercial trucks and trailers. Experience performing A and B preventive maintenance services, or comparable scheduled fleet maintenance. Experience diagnosing and repairing DEF, DPF, SCR, regeneration, and other diesel aftertreatment system issues. Strong electrical troubleshooting skills, including batteries, starting and charging systems, wiring, lighting, fuses, relays, connectors, and grounds. Experience inspecting, repairing, replacing, and rotating commercial tires and wheels. Experience inspecting and repairing air brakes, ABS, steering, suspension, wheel bearings, cooling systems, and other safety-related components. Ability to troubleshoot and repair issues found during preventive maintenance and DOT inspections. Ability to use diagnostic equipment, read wiring diagrams and service manuals, and accurately document completed repairs. Must have a valid driver's license and a basic set of mechanic's tools. Must be able to work independently and determine when a vehicle is unsafe to return to service. Preferred Qualifications ASE certifications. Diesel technology or vocational training.