Onboarding plan
Diesel Mechanic Onboarding Plan (30-60-90 Days)
A practical, printable plan to take a new diesel mechanic from first day to full productivity.
Diesel Mechanic onboarding at a glance
Week one covers orientation, safety and shadowing. Days 1–30 build vocabulary and supervised practice on core procedures; days 31–60 move to independent work with competency sign-offs; days 61–90 focus on full productivity, cross-training and a credential plan.
Before day one
- Confirm start date, schedule, pay and supervisor in writing
- Verify required credentials: ASE Medium-Heavy Truck (T-series), DOT annual inspector qualification (as applicable)
- Prepare equipment and access: OEM diagnostic software and laptops; multimeters and scan tools; torque wrenches and impact tools; lifts, jacks and stands
- Assign a buddy or preceptor
- Enroll the new hire in Diesel Mechanic training so foundations are covered before or during week one
Week one: orient and protect
- Workplace tour, emergency procedures and incident reporting
- Chock wheels and support vehicles with jack stands. Never rely on a jack alone
- Lock out and tag out vehicles and equipment during repairs
- Wear eye protection and gloves when working with fluids and pressurized systems
- Cage tires before inflating split-rim or multi-piece wheels
- Shadow an experienced diesel mechanic through a full shift
- Training modules 1–3: role foundations, a day on the job and essential vocabulary (15 terms)
Days 1–30: learn
Goal: perform core tasks safely under supervision.
- Supervised practice: perform a truck PM service
- Supervised practice: check air brake pushrod stroke
- Supervised practice: read heavy-duty fault codes
- Training modules 4–7: duties, step-by-step tasks, tools and safety
- 30-day check-in: confidence, questions and early wins
Days 31–60: contribute
Goal: handle a regular workload independently.
- Perform preventive maintenance inspections and services: independently
- Diagnose problems using diagnostic software and test equipment: independently
- Repair or rebuild engines, transmissions and drivetrains: independently
- Inspect and repair air brakes, steering and suspension: independently
- Competency sign-offs completed (see checklist below)
- Training final knowledge check and certificate of completion
- 60-day check-in
Days 61–90: own
Goal: full productivity and a growth plan.
- Meet productivity and quality targets for the role
- Begin cross-training on a secondary task
- Agree on a credential goal (for example, ASE Medium-Heavy Truck (T-series))
- Discuss the career path: Lube Tech or Apprentice → Diesel Technician → Master or Lead Technician
- 90-day review
Competency checklist
| Skill or task | Trained | Observed | Signed off |
|---|---|---|---|
| Perform a Truck PM Service | |||
| Check Air Brake Pushrod Stroke | |||
| Read Heavy-Duty Fault Codes | |||
| Diesel engine diagnostics | |||
| Air brake systems | |||
| Electrical and electronic troubleshooting | |||
| Aftertreatment (DPF, DEF, SCR) |
How to measure onboarding success
- Time to independent work orders
- Comeback, rework or scrap rate
- Billable or productive hours versus target
- 90-day retention
How Diesel Mechanic training maps to this plan
- Introduction to the Diesel Mechanic Role
- A Day on the Job
- Essential Diesel Mechanic Vocabulary
- Core Duties and Responsibilities
- Common Tasks, Step by Step
- Tools, Equipment and Technology
- Safety, Compliance and Professional Standards
- Skills Employers Look For
- Launching Your Diesel Mechanic Career
- Final Knowledge Check