Performs maintenance, troubleshooting, and major repair on heavy-duty mobile equipment, combat, tactical, and automotive vehicles. This may include self-propelled artillery, tracked cargo and personnel carriers, road graders, mobile cranes, front loaders, bulldozers, power shovels, tanks, tracked combat vehicles, all terrain vehicles, semi trailers, forklifts, tractors, and accessory equipment. Troubleshoots, repairs and/or overhauls, as a regular and recurring duty, a variety of the mechanically complex major systems to include internal combustion engines, turbine engines, automatic and non-automatic transmissions, heavy duty drive line systems, and hydraulic utility systems and controls, cross drive or similar multi-system transmissions and a variety of intricate fuel injection systems. Makes repairs and modifications to assemblies and components such as voltage regulators, generators/alternators, brake cylinders, etc., for use or placement in systems for which they were not specifically designed. Improvises work when standard procedures do not apply. Troubleshoots equipment with a variety of the mechanically complex major systems and diagnoses difficult performance problems and the cause of mechanical failures by means of visual and auditory checks, uses test equipment such as engine analyzers, compression testers, voltmeters, ohmmeters, pressure gauges and computer diagnostic tools. Utilizes embedded diagnostics in equipment and a wide variety of specialized original equipment manufacturer system analyzers in order to determine the exact nature or extent of repair. Determines what adjustments may be necessary to complete work orders, and whether any additional repairs other than those specified or indicated on the work order are necessary. Removes and disassembles engines and complex major assemblies, sub-assemblies, components, and fuel, hydraulic, and oil pressure systems. Makes the appropriate repairs, overhaul, or modifications in accordance with the proper repair specifications and procedures, and improvises repair techniques when standard procedures are not available. Reassembles engines and other systems, and adjusts, tests, and reinstalls in vehicles and equipment as necessary. Makes adjustments and repairs to electrical and suspension systems. Repairs equipment with a variety of interconnected systems to include state of the art electrical and electronic, fuel injection, interconnected gear reduction, multiple engine, and similarly complex systems. Improvises, substitutes, or alters components or parts to fit into systems for which the items were not specially designed or finds other ways to correct defects when existing methods and procedures do not give desired results. Independently performs repairs and maintenance functions with little or no supervision in remote locations. Provides technical guidance and specialized team leadership to lower grade employees within the team. Assists lower grade mechanics in performing major repair work on interconnected complex systems such as electrical, air and hydraulic systems, complex state of the art electrical and electronic systems that use specialized diagnostic equipment to identify problems, complex fuel injection systems and other similar complex systems. May provide Field and limited Sustainment maintenance at unit locations as part of a contact team. Conducts readiness and repair inspections on vehicles and associated equipment supported by the activity. Performs operational inspections and ensures vehicles and equipment are properly serviced, including brake adjustments, replacing hydraulic fluids, greasing, cleaning, etc., and performs other preventive maintenance operations as required. Inspects supported equipment prior to use during Inactive Duty Training (IDT) and Annual Training (AT), to ensure that it is functioning properly. May inspect in-process repair work of lower graded repairer to ensure equipment is being repaired in accordance with pertinent requirements. May serve as a commodity inspector during Command Maintenance Management evaluations (COMET) or as a member of a Maintenance Assistance Instruction Team (MAIT). Instructs operator/crew in the maintenance of equipment and provides technical advice and assistance to supported units when requested. Performs electrical repairs on complex state of the art electrical and electronic systems requiring extensive training on specialized diagnostic equipment to identify problems. Assists in the maintenance of production reports and records, and makes recommendations to the supervisor. Plans, organizes, and performs technical analyses as required or assigned. Makes recommendations to the supervisor as to adjustments necessary to effectively, efficiently and economically accomplish the work and maximize production. Performs other duties as assigned.