Your Mack Deserves More Than Just Another Repair Shop
You know that feeling. The dash lights up on your Mack Anthem halfway through a haul, the engine loses power, and suddenly you’re doing math in your head — how many days down, how many loads missed, how many phone calls to make. A truck that isn’t running is a paycheck that isn’t coming. And the last shop that had it for a week still couldn’t tell you what was actually wrong.
Note: Large vehicles like this are serviced at our Greeley and Fort Morgan locations. Our Brighton shop handles cars and light trucks.
At Bullet Automotive & Diesel, at, with locations in Greeley and Fort Morgan, CO, we work on Mack trucks the way you’d want them worked on — honestly, quickly, and with the diesel knowledge to actually diagnose the problem the first time. Whether you run a Granite, Anthem, Pinnacle, or an older CH or Vision, our ASE Certified technicians treat your rig like the livelihood it is. We shoot straight, every time.
Why Mack Owners in Greeley and Fort Morgan Choose Bullet Automotive & Diesel
We Speak Your Language, Not Mechanic Jargon
You know your way around an engine. You don’t need to be talked down to, and you don’t need a lecture full of shop-talk designed to confuse you into a bigger bill. When you bring your Mack in, here’s what you get:
- A plain-English explanation of what’s actually wrong
- Clear priority tiers — what’s a safety must-fix now versus what can wait
- A written estimate before we touch a single bolt
- Straight answers on how long your truck will be down
- Updates as the work moves, not silence for days
We built this shop for the guy who’s been burned before. No fluff, no guessing games, no surprise line items when you come to pick it up.
Mack Expertise Without Dealership Pricing
Getting a Mack into a dealer often means a long wait and a bill that treats you like a walking wallet. We’re the independent alternative — real heavy-duty diesel capability without the dealership runaround. Our True Diesel Experience shows up in how we handle your truck:
- Technicians who actually work on Mack MP7 and MP8 engines
- and TEXA diagnostic equipment for accurate fault reading
- Fleet Maintenance Repair Specialists on staff
- Comprehensive multi-point vehicle inspections on every visit
- Repairs backed by a 12 month or 12,000 mile warranty
You get the specialist knowledge you’d expect from a dealer, minus the sticker shock and the week-long wait for an appointment.
Transparency That Rebuilds Trust
If you’ve handed your truck to a shop that found ten problems when you came in for one, you know why trust matters. We do things differently:
- Written estimates with no hidden charges
- We only recommend work your truck actually needs
- Photos and evidence of the problem when it helps you decide
- No pressure to fix everything at once
- The same honest answer whether it’s one truck or your whole fleet
Over 800 5-Star Reviews across our locations came from drivers and business owners who kept coming back because we never played games with them.
Comprehensive Mack Repair Services in Greeley and Fort Morgan
Mack Maintenance Services
Keeping a Mack on the road means staying ahead of wear before it turns into a breakdown. Colorado’s temperature swings — from below freezing to over 100 degrees — put real stress on fluids, seals, and cooling systems. Regular maintenance is how you avoid the roadside call.
- Diesel oil and filter changes
- Fuel filter replacement and fuel system service
- Coolant system flushes and inspections
- Air and cabin filter service
- Belt and hose inspection and replacement
- Scheduled fleet and factory maintenance
Talk to us about a scheduled maintenance plan that fits how hard you run your Mack, so nothing slips through the cracks.
Mack Diagnostic and Repair Services
Modern Mack trucks are packed with sensors and systems that a code reader from the parts store won’t sort out. When something’s wrong, we use professional diesel diagnostics to find the root cause instead of throwing parts at it.
- Check engine and warning light diagnostics
- MP7 and MP8 engine repair and rebuilds
- Turbocharger repair and replacement
- Transmission and drivetrain service
- Air brake and hydraulic brake repair
- Suspension and steering repair
From vehicle diagnosis and repair to transmission and drivetrain repair, we handle the heavy work that keeps a Class 8 truck earning.
Mack Specialty Services
Mack’s emissions and aftertreatment systems demand specialized attention — and getting them wrong means derates, downtime, and lost loads. Our specialty diesel work keeps your truck compliant and pulling.
- DPF cleaning and replacement
- EGR valve repair and diesel emissions service
- Diesel injector cleaning and replacement
- mDRIVE automated transmission service
- Fleet-wide preventive maintenance programs
Need full-service diesel support? Our diesel repair services cover everything a Mack can throw at us, and our brake repair and replacement keeps your heaviest loads stopping safely.
Model-Specific Mack Expertise
Mack Anthem Service and Repair
The Anthem is Mack’s flagship on-highway tractor, built for long hauls and fuel efficiency. Owners often see us for MP8 engine performance issues, aftertreatment faults, and mDRIVE transmission concerns. We keep the electronics reading straight and the powertrain pulling strong so your miles stay profitable.
Mack Granite Service and Repair
The Granite is the workhorse of the construction and vocational world — dump trucks, mixers, and heavy hauling. All that stop-and-go and dust takes a toll on brakes, cooling systems, and suspensions. We handle air brake service, heavy suspension repair, and cooling system work to keep your Granite on the job site.
Mack Pinnacle Service and Repair
The Pinnacle bridges regional and long-haul duty with the MP7 and MP8 engine options. Common visits involve turbocharger issues, EGR and DPF problems, and drivetrain wear from steady highway miles. We diagnose the aftertreatment systems properly so you avoid the dreaded engine derate.
Mack CH and Vision Service and Repair
Older CH and Vision models are still earning their keep across Colorado, and we love keeping these proven trucks running. Age brings electrical gremlins, fuel system wear, and cooling challenges. Our technicians know these platforms and source the right parts to keep a seasoned Mack reliable for years more.
Mack TerraPro Service and Repair
The TerraPro is built for refuse and municipal work, running hard in demanding low-speed, high-cycle conditions. That duty cycle is brutal on transmissions, brakes, and hydraulics. We service the drivetrain, brake systems, and cooling components that keep these vocational trucks completing routes without interruption.
Common Issues Across Mack Models
Every make has its patterns, and Macks are no exception. Here are the issues we see most often and how we handle them:
- Aftertreatment and DPF faults: Clogged filters and EGR problems trigger derates that kill your power on the highway. We clean, repair, or replace the affected components and clear the system properly.
- MP engine sensor failures: Faulty sensors throw misleading codes that lead cheaper shops to replace the wrong parts. Our and TEXA equipment pinpoints the real culprit.
- Turbocharger wear: Loss of power and excessive smoke often trace back to turbo issues. We inspect, repair, or replace turbos and check the feed lines that caused the failure.
- mDRIVE transmission concerns: Automated manual gearboxes need proper service and calibration. We diagnose shifting problems and keep the software and mechanicals in sync.
- Cooling system stress: Colorado heat above 100 degrees pushes cooling systems hard, especially loaded on a grade. We test, flush, and repair radiators, water pumps, and thermostats.
- Fuel system and injector problems: Rough idle and hard starts often mean injector or fuel filter trouble. We clean or replace injectors and service the full fuel system.
The Bullet Automotive & Diesel Difference for Mack Owners
You don’t just need a repair — you need a shop you can stop second-guessing. Here’s what working with us looks like:
- Respects your time with fast, efficient turnaround that gets your truck back to earning
- Respects your wallet with transparent, written pricing and no surprise line items
- Respects your knowledge by explaining the problem in plain English, never talking down to you
- Respects your business with fleet-ready service whether you run one Mack or four
The goal is simple: a Mack you never have to worry about and a shop you never have to second-guess. That’s the relationship we build, one honest repair at a time.
Service Areas We Serve
We keep Mack trucks running for owner-operators and fleets across the Front Range and beyond:
- Greeley and Fort Morgan, CO — our home shop in Greeley and Fort Morgan
- Greeley, CO — full diesel service for northern Weld County
- Fort Morgan, CO — heavy-duty support out east
- Fort Lupton, CO — convenient service along the corridor
- Commerce City, CO — a short haul from our Greeley and Fort Morgan service bays
- Thornton, CO — trusted diesel repair nearby
Schedule Your Mack Service Today in Greeley and Fort Morgan, CO
When your Mack is down, every hour counts — so let’s get it diagnosed right and back on the road fast. Bring your truck to a shop that treats your livelihood like it matters, because it does.
Bullet Automotive & Diesel
Greeley: 624 13th St., Greeley, CO 80631 · 970-415-8018
Fort Morgan: 100 Walnut St., Fort Morgan, CO 80701 · 970-867-2519
Read what other Mack and diesel owners say on our reviews page, then call us to set up your service. We always shoot straight — call Bullet Automotive & Diesel today at 970-415-8018.