Rosalind Achebe-Thornquist

Heavy-Duty Diesel Fleet Mechanic

Tulsa, OK, United States

Professional Summary

ASE Master-certified heavy-duty diesel mechanic with 12+ years maintaining Class 6–8 tractors, transit buses, and vocational trucks. Specialist in Cummins, Detroit, and PACCAR engine diagnostics, DPF/SCR/DEF aftertreatment repair, and air brake systems. DOT-qualified annual inspector and CDL Class A holder known for cutting unplanned downtime 31%, sustaining 98%+ PM compliance, and mentoring apprentices into ASE-certified technicians.

Employment History

Lead Diesel Technician

Red Dirt Freight Lines · Tulsa, OK

Mar, 2020 · Present

Lead a 9-technician shop maintaining 240 Class 8 tractors (Freightliner Cascadia, Peterbilt 579, Kenworth T680) and 410 trailers across two terminals. Raised PM on-time compliance from 86% to 98.7% by rebuilding PM intervals in Fleetio and staging parts kits ahead of scheduled service. Cut unplanned downtime per unit 31% (4.2 to 2.9 days) through root-cause analysis of repeat DPF, SCR, and EGR aftertreatment failures. Perform 300+ DOT annual inspections per year; fleet roadside out-of-service rate fell from 7.1% to 2.4%. Diagnose Cummins X15, Detroit DD15, and PACCAR MX-13 faults with INSITE, DiagnosticLink, and JPRO, bringing $186K/yr of outsourced engine work in-house. Mentored 6 apprentices on air brakes, electrical, and aftertreatment; 5 earned ASE T-series certifications within 24 months.

Diesel Mechanic

Tulsa Metro Transit Authority · Tulsa, OK

Jun, 2016 · Feb, 2020

Maintained 120 Gillig and New Flyer transit buses (Cummins L9/ISL diesel and CNG) plus 45 paratransit vehicles. Improved mean distance between road calls 22% by standardizing air brake, ABS, and HVAC inspection checklists. Diagnosed SCR doser, DEF pump, and NOx sensor faults, reducing aftertreatment-related road calls 35%. Rebuilt Allison B400R transmissions and Voith retarders in-house, saving $54K per year versus vendor rebuilds. Completed 100% of FTA-required 6,000-mile inspections on schedule across three consecutive audit cycles.

Apprentice / Lube Technician

Sooner Truck Center (Peterbilt Dealer) · Tulsa, OK

May, 2013 · May, 2016

Completed 2,500+ PM services, oil analysis samples, and chassis lubes on Peterbilt and Kenworth trucks. Promoted from lube tech to apprentice mechanic in 14 months; assisted on in-frame overhauls of PACCAR MX-13 and Cummins ISX engines. Performed brake adjustments, slack adjuster and chamber replacements, and wheel-end service on 30+ units per week. MIG and stick welded brackets, frame repairs, and liftgate mounts with zero safety incidents over three years.

Education

Associate of Applied Science, Diesel & Heavy Equipment Technology

OSU Institute of Technology · Okmulgee, OK

Aug, 2013 · May, 2015

Cummins and PACCAR partner program; coursework in electronic engine controls, hydraulics, HVAC, and drivetrain. GPA 3.7; Dean's List four terms.

Diesel Technology Certificate

Tulsa Tech · Tulsa, OK

Aug, 2012 · May, 2013

Engine fundamentals, air brake systems, preventive maintenance, and SMAW/GMAW welding.

Skills

Cummins INSITE

Detroit Diesel DiagnosticLink

Noregon JPRO

PACCAR DAVIE4 & Allison DOC

DPF / SCR / EGR Aftertreatment

Air Brakes & ABS

Engine Overhauls (X15, DD15, MX-13)

Hydraulics, PTO & Wet Kits

J1939 CAN Bus Electrical Diagnostics

MIG, Stick & Oxy-Acetylene Welding

PM Program Management (Fleetio)

DOT / FMCSA Compliance

Courses

ASE Medium-Heavy Truck Master Technician (T2–T8)

National Institute for Automotive Service Excellence

Jan, 2019

Commercial Driver License Class A, Air Brakes Endorsement

Oklahoma Department of Public Safety

Apr, 2014

EPA Section 609 Refrigerant Recovery Certification

U.S. Environmental Protection Agency / MACS

Jun, 2016

DOT Annual Inspector Qualification (49 CFR 396.19)

FMCSA / Red Dirt Freight Lines

Mar, 2020

Aftertreatment & Electronic Controls Factory Training

Cummins Inc. and Detroit Diesel

Sep, 2021