Diagnose and Repair: Troubleshoot complex mechanical, hydraulic, electrical, and electronic systems on heavy-duty diesel trucks using advanced diagnostic tools, schematics, and technical manuals (e.g., Cummins Insite, Detroit Diesel Diagnostic Link). Perform Maintenance: Conduct routine preventive maintenance, including oil changes, filter replacements, tire inspections, brake adjustments, and chassis lubrication to ensure reliability and compliance with federal and state regulations.