Fleet Maintenance Technician (Trucks) Career Overview

Fleet maintenance technicians keep commercial trucks safe, compliant, and on the road. They inspect, diagnose, and repair diesel and gasoline vehicles, tractors, and trailers for carriers, municipalities, leasing companies, and private fleets. The role combines hands-on mechanical work with electronic diagnostics, documentation, and customer service to minimize downtime.

What Fleet Maintenance Technicians Do

• Perform PM services, DOT inspections, and multi-point checks on tractors and trailers

• Diagnose and repair engines, cooling systems, fuel systems, turbochargers, and aftertreatment including DPF, DEF, EGR, and SCR

• Service drivetrains, clutches, transmissions, differentials, and axles

• Maintain brake, steering, and suspension systems including air brakes and alignment-related components

• Troubleshoot electrical and electronic faults including batteries, starters, alternators, lights, ABS, and CAN bus issues

• Handle tires, wheels, hubs, and wheel-end bearings; perform road calls and mobile repairs

• Document work orders, parts, and labor in a CMMS to support compliance and warranty claims

Where They Work

• Truck dealers, leasing and rental companies, and independent repair shops

• Private and for-hire fleets in logistics, food and beverage, construction, utilities, and municipalities

• Shop bays, field service trucks, and roadside environments across multiple shifts

Must-Have Skills

• Strong diesel fundamentals and systematic troubleshooting under time pressure

• Air brake systems, ABS, and wheel-end service proficiency

• Aftertreatment and emissions diagnostics to resolve derates and regen issues

• Electrical testing with wiring diagrams and connectors on modern multiplexed systems

• Hydraulics and PTO accessories for vocational trucks

• Clear communication with dispatch, drivers, and parts suppliers

Training and Certifications

• Technical diploma or apprenticeship in diesel technology is common

• ASE Medium/Heavy Truck tests such as T2 Diesel Engines, T4 Brakes, T5 Suspension and Steering, T6 Electrical/Electronic Systems, T8 PM Inspection

• CDL helpful for test drives and moving equipment

• EPA 609 for mobile A/C service; forklift and aerial lift cards where applicable

• OEM and vendor training for engines, transmissions, ABS, and aftertreatment systems

Tools and Technology

• Scan tools and software for engines, ABS, and transmissions plus laptop-based diagnostics

• Multimeters, amp clamps, pressure and vacuum gauges, smoke machines, and breakout leads

• Torque wrenches, pullers, bearing heaters, air tools, and mobile service equipment

• Telematics dashboards and fault code portals to prioritize work and reduce repeat failures

Safety and Compliance Essentials

• Lockout/tagout, wheel chocks, jack stands, cribbing, and safe lifting practices

• Air brake caging and proper de-energizing of high-pressure lines

• Diesel exhaust and chemical handling with proper PPE

• DOT, FMCSA, and OEM inspection standards with accurate records and sign-offs

Career Path

• PM Tech or Tire Tech → A/B Level Technician → Lead Tech or Shop Foreman → Mobile Field Tech or Diagnostic Specialist → Maintenance Supervisor or Fleet Manager

• Specializations include diagnostics, emissions, trailer refrigeration, hydraulics, and EV/alt-fuel trucks

Breaking In

• Start with PM services and inspections to build speed and quality

• Log solved faults and repeat-failure fixes; learn one engine and one transmission platform deeply

• Strengthen electrical and aftertreatment skills through OEM courses and ASE exams

• Develop clear notes and parts lists that help the next tech and reduce comeback time

Key Takeaway
Fleet maintenance technicians are critical to uptime and safety in trucking. Pros who mix solid mechanical skill with electrical and emissions diagnostics, documentation discipline, and road-ready safety habits advance quickly and earn trust across the fleet.

Source: ChatGPT