Diesel Mechanic Job Description: Duties, Requirements, Template & Pay (2026)
A diesel mechanic — diesel technician on half the postings, and the same job — diagnoses, repairs and maintains heavy trucks, buses and equipment, and increasingly spends as much time with a laptop as with a wrench. This page has a diesel mechanic job description template you can copy, the requirements that belong in it, what technicians are paid by industry, and the lines in a posting that decide whether experienced techs apply.
Diesel mechanic or diesel technician? Use both
These are the same job under two names, and the split in search is close to even. Employers in fleet, dealer and equipment settings have mostly moved to "technician" because the work is now diagnostic; independent shops and owner-operators still say "mechanic". Candidates search both.
The practical answer is to put one in the job title and the other in the first two lines of the summary: "Diesel Technician (Diesel Mechanic) — Class 8 fleet". You lose nothing and you stop splitting your own audience in half.
What a diesel mechanic does
The job has moved. A modern heavy-duty technician spends a large share of the week on diagnostics — fault codes, live data, aftertreatment and emissions systems, electrical and network faults — and the rest on the physical work: engines, drivetrain, brakes and air systems, suspension, steering, hydraulics, HVAC and preventive maintenance inspections.
What differs between employers is the mix and the pace. In a fleet shop the week is PM services, DOT inspections, brake jobs and keeping units out of the yard, with one eye on downtime cost. In a dealer it is warranty work, manufacturer diagnostics, flat-rate pressure and factory training. In mobile and roadside it is diagnostics with what is in the truck, in weather, alone. In construction and agricultural equipment it is hydraulics, undercarriage and machine-specific systems, often on site.
Technicians self-select hard on that mix, and the posting that names it gets better applicants than the posting that lists every duty a diesel technician has ever performed. Say which type of shop you are in the first two lines.
Diesel mechanic job description template
Copy this into your ATS or job board, replace the bracketed fields, and delete what does not apply. It is written for a fleet or independent heavy-duty shop; the customization section covers dealer, mobile, equipment and transit work.
Job title
Diesel Technician (Diesel Mechanic) — [Fleet / Dealer / Mobile / Heavy Equipment], [Company name], [City, ST]
Summary
[Company name] is hiring a diesel technician for our [city] shop. We run [number] [Class 8 tractors / trailers / buses / machines] — mostly [makes] — with [number] technicians on [shift pattern]. Pay is [$00.00–$00.00] an hour depending on experience and certifications, [hourly, not flat rate], with [overtime after 40 / a shift differential for nights]. [We supply diagnostic laptops and specialty tools; you bring hand tools, and we pay a tool allowance of [$000] a year.]
Responsibilities
- Diagnose engine, aftertreatment, electrical and drivetrain faults using [OEM software, JPRO, Cummins Insite, DDDL]
- Perform preventive maintenance services and DOT annual inspections to schedule
- Repair and replace brakes, air systems, suspension, steering and driveline components
- Service and repair hydraulic, HVAC and electrical systems
- Complete engine and aftertreatment repairs, including [in-frame overhauls / DPF and EGR service]
- Road-test units and verify the repair before release
- Document every job accurately in [shop management system]: complaint, cause, correction, parts and time
- Keep the bay, tools and shop safe and orderly; follow lockout and PPE procedures
- Flag recurring failures and parts issues so the fleet can act on them
Requirements
- [00] years of heavy-duty diesel experience, or completion of a diesel technology program
- Own hand tools appropriate to the level; [we supply specialty tools and diagnostic equipment]
- Valid driver's licence; [CDL or willingness to obtain one within [00] days — we pay]
- Able to lift [50] lbs, work on your feet and in confined positions
- Able to pass a background check and [DOT drug screen]
Preferred
- ASE certifications (T-series), or [manufacturer] factory training
- Experience with [Cummins, Detroit, Paccar, Volvo, CAT, International] engines
- Aftertreatment and emissions diagnostic experience
- [Air conditioning 609 certification]
- [Welding and fabrication]
Pay and benefits
- [$00.00–$00.00] an hour, hourly rather than flat rate, reviewed at [6/12] months
- [Certification pay: [$0.00] an hour per ASE held]
- [Annual tool allowance of [$000] and a boot allowance]
- [We pay for ASE testing and manufacturer training, on the clock]
- [Health, dental and vision from day [00]], [401(k) with match], [PTO and paid holidays]
- [Uniforms laundered], [climate-controlled shop], [no weekends]
How to apply
[Apply here / text DIESEL to 00000 / call [name] at [number]]. We reply to every application within [24] hours and you can walk the shop before you decide.
Requirements: what is required, what is preferred, and what costs you applicants
There are roughly 24,400 diesel technician openings a year against 4% growth, which means nearly every hire is somebody else's technician. Every unnecessary requirement in the posting is a candidate handed to a competitor.
| Requirement | What to know |
|---|---|
| Years of experience | Ask for the work, not the years. "Can run a PM and diagnose an aftertreatment fault unsupervised" is checkable in an interview; "5+ years" is not, and it excludes a strong second-year tech out of a good program. |
| Own tools | Standard and fair for hand tools — but say what you supply. Diagnostic laptops, software subscriptions and specialty tooling are the employer's, and a posting that says so reads as a properly equipped shop. A tool allowance is worth stating as a number. |
| CDL | Required by some shops for road-testing. It is a real barrier for a technician who does not hold one, and it is cheap to remove: "or obtain within 90 days, we pay" keeps good candidates in the process. |
| ASE certification | Prefer it, pay for it, and pay more for holding it. Requiring T-series ASEs at hire narrows the pool sharply in most markets, and certification pay is a stronger recruiting line than a certification requirement. |
| Manufacturer experience | Name the engines and makes you run, as a preference. Technicians want to know whether their existing knowledge transfers; they do not read it as a gate unless you make it one. |
| Flat rate versus hourly | Not a requirement, but the first thing an experienced technician looks for. If you pay hourly, say so in the summary — in a market with plenty of flat-rate dealer jobs, it is a differentiator worth more than a dollar an hour. |
| DOT drug screen | Name it if you run it. Technicians apply to several shops at once and a surprise screen after acceptance is a common reason a start date falls through. |
Diesel technician duties, written for a posting
A duties list that could apply to any shop tells a technician nothing. The details that decide it are the equipment and the workload: how many units, which makes and engines, how many technicians, how many bays, what the shift pattern is, and whether the shop runs its own PM schedule or fights fires all day.
Say what the work mix is as a rough split — "roughly half PM and inspections, a third diagnostics and repair, the rest breakdowns" — and whether roadside calls are part of the job. Roadside is the single most under-disclosed duty in this trade and one of the largest causes of early exits.
Keep the list to eight or nine lines, order it by how much of the week each takes, and include the documentation. Technicians know the paperwork is part of the job; a shop that pretends otherwise is one they have worked at before.
How to customize it by shop type
Fleet maintenance
Lead with fleet size, makes and the PM schedule, and say what downtime costs you — technicians respect a shop that measures it. State the shift pattern honestly, including whether there is a night shift, and say whether the shop is climate-controlled.
Dealer service
Your advantages are factory training, tooling and warranty work. Your disadvantage in a technician's eyes is flat rate and the hours it can hide. Say the pay structure plainly, say how training is paid, and name the manufacturer certification path.
Mobile and roadside service
Different job, different candidate. Say what the truck carries, the on-call rotation, how calls are dispatched, whether the vehicle goes home, and how overnight and callout pay works. Technicians who want this work want autonomy; the ones who do not will select out, which is the point.
Heavy equipment and agricultural
Hydraulics, undercarriage, implements and field service, often on a job site or a farm. Name the brands, say how much of the work is on site versus in the shop, and say who owns the service truck.
Transit and school bus
Sell what this segment actually has: regular hours, no flat rate, public-sector benefits and, per BLS, the highest median pay of any diesel employer type — $71,460 a year in local government. Say the shift pattern and the seasonal peaks.
What it costs to reach diesel technicians on social
Technician and mechanic roles are our largest single role family: across 145 campaigns in the 2026 Social Job Advertising Benchmark the median cost per applicant was $13.41, the middle half $7.40 to $23.58, with a blended figure of $8.35, a 16% apply rate and a 1.17% click-through rate. The wider skilled trades and field service sector — 335 campaigns — ran a $11.89 median at an 18% apply rate.
For a hard-to-fill technical role, the two things that move that number are the apply rate and frequency. Campaigns converting under 10% of clicks paid a median $53.77 an applicant; over 20%, $4.41. And once the same technician has seen the ad more than three times in a month, the median cost per applicant roughly doubles — which for a small local pool of heavy-duty techs happens faster than employers expect. The fix is a better offer in the ad, not more budget behind the same one.
If the harder problem is the pipeline rather than the posting, see the mechanic job description for the automotive version of this role and skilled trades recruiting for the hiring side.
Writing the ad version
The description is the document; the advertisement is read on a phone in a break room by somebody who already has a job in a shop. It needs the pay range, the pay structure, the shop type and the tools you supply — in that order. Our campaign data puts the best-converting length at 201–400 words.
Four questions on the form is the ceiling: years of heavy-duty experience, engines or makes worked on, certifications held, and when they can start. Anything asking for an employment history before a conversation costs you completions in a trade where candidates are choosing between three shops that all want to talk to them.
What diesel mechanics earn, by industry
The national median was $29.70 an hour, $61,770 a year in May 2025. The industry spread is about $11,600 a year between the top and the bottom, and it does not run the way most people assume — local government pays best and truck transportation, the largest employer, pays least.
| Industry | Median annual pay (May 2025) | Share of technicians employed |
|---|---|---|
| Local government (excluding education and hospitals) | $71,460 | 9% |
| Wholesale trade | $63,070 | 13% |
| Automotive repair and maintenance | $60,330 | 9% |
| Rental and leasing services | $60,220 | 6% |
| Truck transportation | $59,820 | 18% |
Employment is projected to grow 4% between 2025 and 2035, with about 24,400 openings a year — mostly replacing technicians who retire or move into supervision, parts or fleet management. That is a market where a private fleet is competing against a municipal shop paying roughly $11,600 more a year for the same skills, on daytime hours, with a pension. If you cannot match the number, the posting has to win on the things you control: pay structure, tools, training, shift pattern and the condition of the shop.
Frequently asked questions
What does a diesel mechanic do?
A diesel mechanic diagnoses and repairs heavy-duty engines and the systems around them: aftertreatment and emissions, electrical and network faults, drivetrain, brakes and air systems, suspension and steering, hydraulics and HVAC. They also run preventive maintenance services and DOT inspections, road-test units to verify repairs, and document complaint, cause and correction for each job.
Is a diesel mechanic the same as a diesel technician?
Yes. The two titles describe the same occupation, and BLS classifies them together as diesel service technicians and mechanics. "Technician" has become the more common term in fleet, dealer and equipment settings because the work is now heavily diagnostic. Since candidates search both terms, the best practice is to put one in the title and the other in the opening lines.
What qualifications does a diesel mechanic need?
A high school diploma or equivalent plus long-term on-the-job training is the typical path, and many technicians also complete a diesel technology program. ASE T-series certifications and manufacturer training are widely valued, and some employers require a CDL for road-testing. Employers usually expect a technician to own their hand tools while the shop supplies diagnostic equipment and specialty tooling.
How much do diesel mechanics make?
The national median was $29.70 an hour, or $61,770 a year, in May 2025 (BLS). By industry, local government pays a median of $71,460, wholesale trade $63,070, automotive repair $60,330, rental and leasing $60,220, and truck transportation — the largest employer at 18% — $59,820.
Do diesel technicians need ASE certification?
It is rarely a legal requirement and is usually treated as a preference, though some employers require or prefer it. In a market this tight, certification pay works better than a certification requirement: pay a differential per ASE held and pay for the testing, rather than excluding technicians who have the skills but not the card.
What should a diesel mechanic job description include?
A title carrying both "technician" and "mechanic", a summary naming fleet size, makes and engines, technician headcount and shift pattern, an hourly pay range with the pay structure stated, eight or nine responsibilities including diagnostics and documentation, required versus preferred certifications, what tools and software you supply, the tool allowance, and a clear way to apply.
Should diesel technicians be paid flat rate or hourly?
Both are used — dealers commonly run flat rate and fleets commonly run hourly. For recruiting purposes what matters is saying which one you use in the summary rather than leaving it to the interview. In a market with plenty of flat-rate work available, an hourly shop that says so up front has a genuine advantage worth more than a small difference in rate.
Why is it so hard to hire diesel mechanics?
Because the pool is barely growing — 4% projected growth with around 24,400 mostly replacement openings a year — so almost every hire comes from another shop. Technicians also have visible alternatives: municipal and transit shops pay a median $71,460 on regular hours. A posting competes on pay structure, tooling, training, shift pattern and shop conditions, not on the word "opportunity".
Other job description templates
Hiring diesel technicians?
The description is the document. Reaching technicians who are already in somebody else's bay is the job. That is what we run.
Pay, employment and outlook figures: U.S. Bureau of Labor Statistics, Occupational Outlook Handbook, Diesel Service Technicians and Mechanics (May 2025 wage data, 2025–35 projections). Cost-per-applicant, apply-rate and frequency figures: Boostpoint 2026 Social Job Advertising Benchmark, 891 campaigns and 1,334 campaign-months.