Diesel Technician III

Unlimited Carrier Inc; Illinois; On-site; USD 52,000 - 59,000; Full time

Job summary

Unlimited Carrier Inc is seeking a senior Diesel Technician III to diagnose and repair diesel-powered trucks and equipment. You will lead and mentor junior technicians, ensuring high-quality repairs and compliance with safety standards.

You will perform advanced diagnostics, component replacements, PMs, and documentation, while coordinating with shop leadership and ensuring efficient maintenance workflows. This role requires physical fitness and strong problem-solving in a shop setting.

Qualifications

• Minimum of 5 years of experience in diesel truck or heavy equipment repair.
• Advanced diagnostic skills using OEM software such as Cummins INSITE, Detroit DiagnosticLink, and Navistar Service Software.
• Strong understanding of electrical systems, aftertreatment systems, and vehicle data networks.
• Ability to read and interpret complex wiring diagrams, schematics, and service manuals.
• Valid driver's license.
• Ability to lift 50+ pounds and perform physically demanding work.

Responsibilities

• Perform expert-level diagnostics on mechanical, electrical, aftertreatment, and driveline systems.
• Troubleshoot and repair: diesel engines, aftertreatment and emissions systems, CAN bus systems, high-level electrical faults, transmission and driveline components.
• Conduct engine performance testing, calibrations, and software updates using OEM diagnostic tools.
• Perform engine component replacement, including turbochargers, injectors, EGR systems, and pumps; replace major assemblies like transmissions, differentials, axles; execute brake, suspension, and steering repairs.
• Conduct and verify all levels of preventative maintenance (PM A, B, and C), including advanced inspection points and DOT inspections.
• Mentor and train Technicians I and II; serve as a technical resource and support shop leadership in quality control.
• Document repairs, diagnostics, and parts usage in maintenance systems; contribute to SOP improvements.
• Lead by example in following safety protocols and PPE; ensure proper use and care of tools and devices.

Skills

Diesel diagnostics

Electrical systems

Wiring diagrams

Driver's license

Physical ability

Education

ASE Certifications

Diesel technology education

Tools

Cummins INSITE

Detroit DiagnosticLink

Navistar Service Software

Job description

Job Description

Job Description

Job DescriptionJob Details

Job Title: Diesel Technician III
Department: Truck Service Point
Reports To: Shop Foreman
Effective Date: 08/04/2026

Position Overview

The Diesel Technician III is a highly skilled, senior-level technician responsible for performing complex diagnostics and advanced repairs on diesel-powered trucks and related equipment. This role serves as a technical expert within the shop, providing leadership, mentoring junior technicians, and ensuring high-quality repair standards.

Key Duties and ResponsibilitiesAdvanced Diagnostics & Repair

• Perform expert-level diagnostics on complex mechanical, electrical, aftertreatment, and driveline systems.
• Troubleshoot and repair:
  • Diesel engines
  • Aftertreatment and emissions systems (DPF, DOC, SCR)
  • Multiplexing and CAN bus systems
  • High-level electrical faults and communication issues
  • Transmission and driveline components
• Conduct engine performance testing, calibrations, and software updates using OEM diagnostic tools.

Major Component Repair

• Perform engine component replacement, including turbochargers, injectors, EGR systems, and pumps.
• Replace major assemblies such as transmissions, differentials, and axles.
• Execute advanced brake, suspension, and steering repairs.

Preventative Maintenance & Compliance

• Conduct and verify all levels of preventative maintenance (PM A, B, and C), including advanced inspection points.
• Perform DOT inspections and ensure full regulatory compliance.
• Identify root causes of recurring fleet issues and recommend corrective actions.

Leadership, Training & Technical Support

• Mentor and train Technicians I and II on best practices, troubleshooting, and repair procedures.
• Serve as a technical resource for complex job assignments.
• Support shop leadership in quality control initiatives.

Documentation & Reporting

• Document repairs, diagnostics, and parts usage accurately in maintenance systems.
• Contribute to procedural improvements and standard operating practices.

Safety & Shop Standards

• Lead by example in following all safety protocols and PPE requirements.
• Identify hazards and take corrective action to maintain a safe work environment.
• Ensure proper use and care of shop tools, equipment, and diagnostic devices.

Skills and RequirementsRequired Qualifications

• Minimum of 5 years of experience in diesel truck or heavy equipment repair.
• Advanced diagnostic skills using OEM software such as Cummins INSITE, Detroit DiagnosticLink, and Navistar Service Software.
• Strong understanding of electrical systems, aftertreatment systems, and vehicle data networks.
• Ability to read and interpret complex wiring diagrams, schematics, and service manuals.
• Valid driver's license.
• Ability to lift 50+ pounds and perform physically demanding work.

Preferred Qualifications

• Formal diesel technology education or equivalent hands‑on experience.
• Multiple ASE Medium/Heavy Truck (T-Series) certifications or ASE Master Certification.
• OEM‑specific training or certifications (Cummins, Detroit, PACCAR, Navistar, Allison).
• Experience training or mentoring other technicians.
• Strong communication and leadership skills.
• CDL Class A or B license.

Work Environment

• Shop environment with exposure to noise, fumes, and heavy machinery.
• Requires standing, bending, lifting, and use of heavy tools.
• May require occasional outdoor work depending on facility setup.

Compensation

Pay Range: $38.00-$43.00 per hour, based on experience, certifications, and shift.

Schedule

• Monday-Friday, 10:00 AM - 6:30 PM

Additional Information

The information contained in this job description is intended to describe the general nature and level of work performed by associates within this classification. It is not intended to be, nor should it be interpreted as, a comprehensive inventory of all duties, responsibilities, or qualifications required of associates assigned to this position.

Include shift schedule

English (US)

Monday-Friday, 10:00 AM - 6:30 PM

Include budgeted hours

Not Included