Diesel Technician III

Unlimited-Carrier; Bolingbrook (IL); On-site; USD 52,000 - 59,000; Full time

Job summary

Unlimited-Carrier in Bolingbrook, IL is seeking a Diesel Technician III to perform complex diagnostics and advanced repairs on diesel trucks. You will serve as a technical expert, providing leadership and mentoring junior technicians while ensuring high-quality repair standards.

The role focuses on advanced diagnostics, repairing engines, aftertreatment systems, and driveline components, plus documentation and safety compliance in a fast-paced shop.

Qualifications

• Minimum 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 and ability to lift 50+ pounds.

Responsibilities

• Perform expert-level diagnostics and repairs on diesel engines, driveline, and emissions systems.
• Troubleshoot high-level electrical faults, CAN bus networks, and transmissions.
• Conduct engine performance tests and implement software updates using OEM tools.
• Replace major assemblies, including turbochargers, injectors, and axles.
• Mentor Technicians I and II and support shop leadership with quality initiatives.
• Document repairs and parts usage in maintenance systems and ensure safety compliance.

Skills

Diesel repair

Diagnostics

Electrical systems

Wiring diagrams

Heavy equipment

Team mentoring

Tools

Cummins INSITE

Detroit DiagnosticLink

Navistar Service Software

Job description

If you are unable to complete this application due to a disability, contact this employer to ask for an accommodation or an alternative application process.

Full Time Employee Bolingbrook, IL, US

24 days ago Requisition ID: 1090

Salary Range: $38.00 To $43.00 Annually

Job Description

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 Responsibilities

Advanced 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 working environment.
• Ensure proper use and care of shop tools, equipment, and diagnostic devices.

Skills and Requirements

Required 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

• 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.
• 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.