Diesel Mechanic resume example

• Entry level

  Diesel technology graduate with 1,100 lab and shop hours on medium and heavy trucks, covering engines, air brakes, electrical systems and hydraulics. Passed ASE T4 Brakes and T8 Preventive Maintenance Inspection, holds EPA Section 609 and a CDL Class A permit. Completed a 4-month internship doing PM inspections on a 60-truck delivery fleet. Owns a starter tool set.

• Mid level

  Heavy-duty diesel mechanic with seven years in fleet shops, working on Class 8 tractors, refuse trucks and trailers. Diagnoses aftertreatment, J1939 electrical and air brake faults with OEM software, and handles in-frame overhauls and clutch jobs. ASE certified T2 through T8, qualified for DOT annual and brake inspections, and holds a CDL Class A for road testing.

• Senior

  Lead diesel technician and shop foreman with sixteen years on mixed fleets of tractors, vocational trucks and transit buses. Runs a 9-technician shop on two shifts, sets the PM program and tracks road calls weekly. Cut road calls on a 180-unit fleet 41% in eighteen months and keeps PM completion above 97%. ASE Master Medium-Heavy Truck certified.

• Not naming engines and equipment

  Fix: "Repaired diesel trucks" does not tell a foreman if you fit their fleet. Name the engine makes and models, truck brands, transmissions and trailer or reefer units you work on. Note medium-duty versus Class 8, and any off-road or transit work. A fleet that runs one engine family will move your resume forward when it sees that name.

• Skipping aftertreatment and electrical

  Fix: Many breakdowns on newer trucks start with sensors, wiring and emissions systems, not mechanical failure. Show what you do on DPF cleaning and forced regens, SCR and DEF faults, EGR valves and coolers, NOx sensors and J1939 network faults. Mention the diagnostic software you use for each make. These are the skills shops find hardest to hire for.

• No uptime or PM results

  Fix: Fleets judge their shops on uptime and road calls. If you can, show PM inspections completed on schedule, road calls per month before and after your changes, out-of-service violations found at roadside, or repeat repairs. Tie each number to a fleet size so it reads clearly, such as "a 140-tractor fleet."

• Burying safety and compliance

  Fix: Shop work involves heavy lifts, air systems, jacks, stands and sometimes high-voltage systems on newer trucks. Show your training: OSHA 10, shop lift and crane rigging if you have it, and lockout procedures. Add DOT inspection qualifications and refrigerant certification. These credentials let a foreman put you on more jobs right away.

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• Cut road calls on a 180-tractor fleet 41% in eighteen months by adding aftertreatment checks and coolant testing to every PM inspection.
• Completed 320 DOT annual inspections in a year as a qualified inspector, with no vehicles placed out of service for missed defects at roadside.
• Diagnosed and repaired 150 aftertreatment faults, including DPF cleanings, NOx sensors and SCR doser failures, with repeat visits under 3%.
• Performed 22 in-frame engine overhauls on Class 8 tractors, each passing a dyno or road test before returning to service.
• Rebuilt the shop's PM schedule in the fleet software, raising on-time PM completion from 84% to 97% across 140 units.
• Traced J1939 network faults on 40 trucks to chafed harnesses and corroded connectors, cutting dash warning comebacks by half.
• Replaced clutches and rebuilt 35 automated manual transmissions, keeping average bay time for the job under two shifts.
• Serviced reefer units and cab A/C on 90 trucks under EPA Section 609, with full refrigerant recovery logs for every job.
• Trained 5 apprentice technicians on air brake adjustment, PM inspections and lockout, each passing ASE T8 within a year.
• Filed 200 warranty claims with full fault codes and photos, getting 94% approved on the first submission.

• Match the fleet and engine makes in the posting

  A fleet that runs one engine family or a dealer tied to one truck brand will scan for those names. Put the matching makes, platforms and software at the top of your skills and first bullets. If the posting mentions transit buses, refuse or reefers, show that equipment. Keep unrelated off-road work shorter unless the job asks for it. Tailor your diesel resume to the fleet

• Write a cover letter around uptime

  Fleet managers think in uptime and road calls. Open your letter with one result, such as a drop in road calls or a PM program you rebuilt. Then list your ASE status, your CDL and the shifts you can cover. Note whether you can take on-call duty or road service. Keep it under a page. Draft a diesel mechanic cover letter

• Practice diagnostic walk-throughs

  Expect questions like: how do you diagnose a derate with an SCR fault, how do you check air brake adjustment, what do you look for in a PM inspection? Some shops add a hands-on test on a truck. Walk through your process out loud, step by step, and be ready to explain one hard fault you found. Practice diesel mechanic interview questions

• Compare with a nearby trade example

  If you also drive or are thinking about a fleet role, see how the truck driver example presents CDL, endorsements and safety records. Borrow the clear credentials line at the top and use it for your ASE, CDL and inspection qualifications, so a foreman sees them all in one place. See the truck driver example