Diesel mechanic job description template: ASE T-series, CDL road tests and DOT testing, brake and annual inspector rules, overtime
On this page
- Which diesel mechanic seat are you hiring?
- The diesel mechanic job description template
- ASE, CDL, FMCSA inspector rules and overtime: the lines with sources
- From must-haves to screening questions and scorecard rows
- Common mistakes in diesel mechanic job descriptions
- Before you publish
- Questions people ask
A diesel mechanic job description should name the seat (fleet shop, truck dealer, independent heavy-duty shop, road service or off-road equipment), the makes and engines, the ASE Medium-Heavy Truck tests that matter (T2 through T8 for Master status), whether the mechanic road-tests trucks on public roads and so needs a CDL and DOT drug testing, and whether they will act as a qualified brake or annual inspector under FMCSA rules. Overtime status depends on the employer: motor carrier and dealership exemptions can apply, independent shops cannot use them. BLS put the national median pay for diesel service technicians and mechanics at $61,770 a year, or $29.70 an hour, in May 2025. Facts below are as of October 2026.
"Diesel tech, own tools, CDL a plus" leaves a candidate guessing whether the job is a dealer bay with OEM software, a carrier's shop running DOT inspections, or a service truck answering roadside calls at night. Each has different credentials, schedules and overtime rules. Below are the seat types, a copy-ready template, the ASE, CDL, FMCSA, EPA, licensing and overtime lines with sources, screening and scorecard rows, and common mistakes. For the call, use diesel mechanic screening questions. For cars and light trucks, start from the automotive technician job description template.
Which diesel mechanic seat are you hiring?
| Seat | What the work looks like | Must-have that separates it |
|---|---|---|
| Fleet shop technician (motor carrier) | The company's tractors and trailers, scheduled PMs, annual inspections, brake work, road tests, records | Keeps PM and inspection records that hold up; qualified to inspect brakes |
| Truck dealer technician | One or two brands, warranty and campaign work, OEM diagnostic software, often flat rate | OEM software and brand training, or the will to complete it |
| Independent heavy-duty shop | Many makes and customers, engine, aftertreatment, drivetrain and electrical repairs | Diagnoses across makes with the software the shop owns |
| Road service or field technician | Service truck, roadside and on-site repairs, tires, on-call nights and weekends | Works alone in all weather; plans parts before driving out |
| Off-road equipment or ag technician | Construction, mining or farm machines, hydraulics, dealer or rental fleets, seasonal peaks | Hydraulic diagnosis on the equipment families you service |
Then settle the facts with the shop manager: makes, engines and the diagnostic software you own; the mix of PM, repair and inspections; whether the mechanic drives trucks on public roads; road calls and on-call; the pay plan; and the tool split. BLS notes that diesel technicians might need a CDL to test-drive buses and large trucks, that some shops offer 24-hour service, and that the work involves heavy parts, uncomfortable positions and occasional roadside or worksite repairs (BLS Occupational Outlook Handbook, last modified August 27, 2026).
The diesel mechanic job description template
Diesel Mechanic — [Fleet / Dealer / Heavy-Duty Shop / Road Service /
Off-Road Equipment], [Day / Night / Weekend] Shift
[Company], [city, state]
Pay: $[min]–$[max] per [hour / flagged hour], plus [shift
differential, on-call pay $N, road-call premium]. [Overtime status,
reviewed for this employer.] [Benefits summary, if required.]
SUMMARY
You will maintain and repair [Class 8 tractors and trailers /
medium-duty trucks / buses / excavators and loaders] — mainly
[makes and engines] — in a [N]-bay shop [and on road calls]. Work
is about [N] percent PM and inspections and [N] percent repair (an
estimate). You will use [diagnostic software] and report to the
[shop foreman / maintenance manager]. On-call is [pattern / none].
WHAT YOU WILL DO
- Diagnose and repair engines, aftertreatment, drivetrain,
[air brakes / hydraulics], electrical and HVAC systems.
- Complete PM services and [annual inspections] and record them in
[maintenance system].
- [Inspect, adjust and repair air brakes as a qualified brake
inspector.]
- [Road-test trucks on public roads (CDL required).]
- [Service cab A/C under our EPA Section 609 procedures.]
- Follow lockout, wheel-chock and lifting procedures on every job.
YOU MUST HAVE
- [N] years on [equipment type], or [diesel program] completion.
- [ASE tests the work needs, e.g. T2, T4, T6 / willing to certify
within N months at our cost.]
- [Class [A/B] CDL, if you road-test on public roads; passing our
DOT pre-employment drug test before you drive.]
- [EPA Section 609 certification, if you service A/C.]
- Valid driver's license [for service-truck seats].
- Ability to climb on equipment, work under vehicles and lift parts
up to [N] pounds [with a hoist above N], in [shop / outdoor]
conditions, with or without reasonable accommodation.
NICE TO HAVE
- ASE Master Medium-Heavy Truck; [OEM] training; welding.
If you meet the must-haves and none of these, please apply.
TOOLS
We provide [lifts, pits, diagnostic laptops and software, specialty
pullers, service truck]. You bring [hand tools], with [tool
allowance, if any].
[EEO STATEMENT]
To request an adjustment to apply or interview, contact [contact].ASE, CDL, FMCSA inspector rules and overtime: the lines with sources
Not legal advice. These points were checked against ASE, FMCSA, 49 CFR Parts 382 and 396 and 40 CFR Part 82 on Cornell's Legal Information Institute, EPA, the Michigan Department of State, the Department of Labor and BLS as of October 2026. State law and your carrier's own procedures add detail.
ASE. The Medium-Heavy Truck series runs from T1 Gasoline Engines to T8 Preventive Maintenance Inspection; technicians certified in T2 through T8 are ASE Certified Master Medium-Heavy Truck Technicians, and certification must be renewed by retesting every five years (ASE T1–T8). The T-series needs two years of full-time hands-on experience, with some training substitutes (ASE work experience instructions). Light vehicle diesel engines fall under A9 in the automobile series. Name the tests the work needs.
CDL and DOT testing. FMCSA's guidance on 49 CFR 383.3 answers "Do mechanics, shop help, and other occasional drivers need a CDL?" with "Yes, if the vehicle is a CMV and is operated or test-driven on a public highway" (FMCSA, issued March 1, 2019). DOT drug and alcohol testing rules then apply to that driver and the employer (49 CFR 382.103), including a drug test before the first time the person performs safety-sensitive functions (49 CFR 382.301). State it in the posting, and see drug testing laws in hiring for how DOT and state rules interact. If the mechanic never drives a CMV on a public road, a CDL is a nice-to-have at most.
Annual and brake inspectors. Motor carriers must ensure that people performing annual inspections understand the inspection criteria and can identify defective components, qualified through a federal or state training program or certificate, or at least one year of combined training and experience (49 CFR 396.19). Anyone responsible for inspecting, maintaining, repairing or servicing CMV brakes must be a qualified brake inspector, through an apprenticeship, training program or state certificate (passing the CDL air brake tests counts for brake inspections) or at least one year of brake-related training or experience (49 CFR 396.25). Carriers keep evidence of these qualifications during the work and for one year after, so ask for it at the offer stage.
EPA Section 609 and state certification. EPA's motor vehicle air conditioning rule defines a motor vehicle as any self-propelled vehicle designed for transporting persons or property on a street or highway (40 CFR 82.32), so trucks and buses are covered: anyone servicing that A/C for pay must be trained and certified by an EPA-approved program (40 CFR 82.34). Michigan also certifies mechanics who repair vehicles for pay, including a Master Heavy-duty Truck Mechanic level for all six heavy-duty categories (Michigan Department of State).
Overtime. The FLSA's motor carrier exemption covers mechanics employed by a motor carrier or motor private carrier whose duties affect the safety of operation of vehicles in interstate commerce. It does not apply in weeks the employee works on vehicles of 10,000 pounds or less, and it does not apply to employees of commercial garages or firms that maintain and repair carriers' vehicles (DOL Fact Sheet #19). Separately, mechanics primarily servicing trucks or farm implements for a dealer that sells them to ultimate purchasers fall under 29 U.S.C. 213(b)(10)(A). Everyone else is a blue-collar worker owed minimum wage and overtime (29 CFR 541.3(a)). Both exemptions remove overtime only, and state law can differ.
Tools and pay. Tool costs passed to a mechanic may not cut pay below minimum wage or into overtime (DOL Fact Sheet #16). The BLS national median for diesel service technicians and mechanics was $61,770 a year ($29.70 an hour) in May 2025. Post your own range, on-call pay and differentials, and check pay transparency laws by state.
From must-haves to screening questions and scorecard rows
| Must-have | Screening question | Scorecard competency | Evidence of a strong answer |
|---|---|---|---|
| Diagnostics | "A tractor comes in with a derate and an aftertreatment code. Walk me through what you check before replacing anything." | Diagnostic method | Reads codes and freeze frame in the OEM software, checks sensors, wiring and aftertreatment data, and tests before ordering parts |
| Air brakes | "How do you check pushrod stroke and what do you do when it is over the limit?" | Brake inspection | Correct procedure, finds the cause rather than only adjusting, documents it |
| CDL (road-test seats) | "Do you hold a Class A or B CDL, and would you be able to pass a DOT pre-employment drug test before driving?" | Not scored | Knockout confirmed |
| Equipment match | "Which engines and makes did you work on most in the last year?" | Relevant experience | Names makes and engines like yours and a repair with a cause and a fix |
| Road calls (field seats) | "On-call is one week in four, nights included. What would make that hard?" | Not scored | Knockout confirmed |
| Tools | "We provide software and specialty tools; mechanics bring hand tools. Do you have a full set for heavy trucks?" | Not scored | Knockout confirmed |
The full call and red flags are in diesel mechanic screening questions; for fleet seats where mechanics also drive, compare truck driver screening questions and the truck driver job description template. The loop and a hands-on task are in the interview guide for automotive roles.
Common mistakes in diesel mechanic job descriptions
"CDL required" when the job never drives
It shrinks the pool and pulls the hire into DOT testing for nothing. Require it only for road tests or moving trucks on public roads.
Requiring a CDL but not mentioning DOT testing
A mechanic who road-tests CMVs is a DOT-tested driver. Say so, so the pre-employment test is not a surprise.
Assuming every diesel seat is overtime-exempt
The motor carrier exemption does not reach commercial garages, and small vehicles change the answer week by week. Check with payroll for this employer.
No makes, engines or software
A dealer technician on one brand's software and an independent shop mechanic are different hires. Name them.
Hiding road calls and on-call
Night roadside work in winter is the condition that ends field hires. State the pattern and the pay for it.
Before you publish
- Seat, equipment, makes, engines and software are in the summary.
- CDL and DOT testing appear only if the mechanic drives CMVs on public roads.
- Brake and annual inspector duties, ASE tests and EPA 609 match the work.
- Overtime status was reviewed for this employer type.
- Pay, on-call, tools, physical tasks, the EEO statement and an accommodation contact are present.
Questions people ask
Does a diesel mechanic need a CDL?
Only if the job includes driving commercial motor vehicles on public roads. FMCSA's guidance says mechanics, shop help and other occasional drivers need a CDL if the vehicle is a commercial motor vehicle and is operated or test-driven on a public highway. A mechanic who will hold a CDL for that work also falls under DOT drug and alcohol testing, including a pre-employment drug test before first driving. If the job never involves that, leave the CDL out of the must-haves.
Are diesel mechanics exempt from overtime?
It depends on the employer. Mechanics employed by a motor carrier whose work affects the safety of vehicles used in interstate commerce can fall under the FLSA's motor carrier overtime exemption, but not in weeks they work on vehicles of 10,000 pounds or less, and the exemption does not cover commercial garages or firms that repair carriers' vehicles. Mechanics at truck and farm equipment dealers may fall under the dealership exemption. Elsewhere, diesel mechanics are owed overtime, and state law may require more.
What is a qualified brake inspector under FMCSA rules?
Under 49 CFR 396.25, a motor carrier must make sure anyone responsible for inspecting, maintaining, repairing or servicing the brakes on its commercial motor vehicles is qualified, either through an apprenticeship, approved training program or state certificate, or through at least one year of brake-related training or experience. The carrier keeps evidence of the qualification while the person does that work and for one year afterward.
Which ASE tests matter for a diesel mechanic job description?
In the Medium-Heavy Truck series, passing T2 through T8, which cover diesel engines, drive train, brakes, suspension and steering, electrical, HVAC and preventive maintenance inspection, makes a technician an ASE Certified Master Medium-Heavy Truck Technician. A9, in the automobile series, covers light vehicle diesel engines. ASE requires two years of hands-on experience for these tests and a retest every five years.