Billings' Trusted Diesel Shop

Your Diesel Deserves
Better Than
a Guess.

From routine maintenance to complex engine diagnostics, we give your truck the honest, expert care it deserves — so you can get back on the road with confidence, not worry.

Call 406-545-7325 Our Services →
Trusted Local Shop
On-Time, Every Time
Expert Technicians
Diesel engine repair in progress at AJ's Auto Diesel Technologies
Heavy-duty diesel truck at the shop
Quality Guaranteed
What We Do

Complete Diesel Care,
Under One Roof

Whether it's a scheduled service or a check-engine light that won't quit, we've got the tools, knowledge, and patience to get it right.

Engine Diagnostics & Repair

Advanced diagnostic tools pinpoint the issue fast — whether it's a sensor glitch or a major overhaul. We explain what's wrong before we touch a bolt.

Preventive Maintenance

Oil changes, filter replacements, fluid checks — the kind of routine care that prevents costly breakdowns down the road. Stay ahead of problems before they find you.

Truck & Diesel Service

From pickup trucks to heavy-duty diesels, we service all makes and models. Fuel systems, turbochargers, EGR — we handle it all with the right expertise.

Brake & Suspension

Brake pads, rotors, shocks, struts — if it connects your wheels to the road, we inspect and service it. Safe stops matter as much as smooth rides.

Electrical Systems

Dead batteries, wiring issues, alternator problems — our electrical diagnostics save you time and frustration. No more guessing games with your truck's wiring.

Emergency Repairs

Breakdowns don't wait, and neither do we. When something goes wrong on the road, bring it in and we'll work fast to get you back moving safely.

Interior of AJ's Auto Diesel Technologies workshop in Billings
Professional automotive tools and equipment
Local Billings, MT
Shop Since Day One
About Us

Built on Hard Work,
Kept Running on Trust

AJ's Auto Diesel Technologies isn't a chain or a franchise — it's a Billings shop built on the idea that your truck deserves honest, straightforward service. We know diesel engines inside and out, and we know how important your vehicle is to your livelihood.

That's why we take the time to explain what's going on, what needs attention, and what can wait. No pressure, no confusing jargon — just clear answers and work that holds up.

📍 Locally Owned & Operated
🔧 All Makes & Models
⭐ Honest, Transparent Pricing
🤝 Customer-First Approach
Visit Our Shop →
Why Choose Us

Not Just Another
Auto Shop

We treat every diesel like it's our own. Here's what sets us apart:

01

Expert Diesel Knowledge

Deep experience with diesel engines means we diagnose faster and fix it right the first time — not a trial-and-error approach.

02

Transparent Communication

We explain the problem in plain language, give you clear options, and never recommend work you don't need.

03

Convenient Billings Location

Easy to find on Old Hardin Road, with straightforward hours that work around your schedule — not the other way around.

04

Fair, Upfront Pricing

No surprise charges or hidden fees. We discuss costs before starting work so you know exactly what to expect.

Close-up of a diesel engine being serviced

Your truck is your livelihood. We treat it with the respect it deserves.

What Customers Say

Trusted by Billings Drivers

Nothing makes us prouder than a satisfied customer who knows their truck is in good hands.

★★★★★

"Brought my truck in with an issue that two other shops couldn't figure out. AJ's team diagnosed it quickly and had it running perfectly. Honest, fair, and they actually care."

M
Mike R. Billings, MT
★★★★★

"Finally found a diesel shop I can trust. They explained everything clearly, didn't try to upsell me, and the price was exactly what they quoted. That's rare these days."

S
Sarah T. Billings, MT
★★★★★

"Great experience from start to finish. They got me in quickly, finished the work on time, and my diesel runs smoother than ever. Highly recommend to anyone in the area."

J
Jason K. Billings, MT

Ready to Get Your Diesel
Running Right?

Give us a call or stop by the shop — we're here to help with whatever your truck needs.

Call 406-545-7325 Send a Message
Contact Us

Let's Talk About
Your Truck

Have a question or need to schedule a service? Reach out however works best for you.

Address 2323 Old Hardin Rd
Billings, MT 59101
Phone 406-545-7325

Send Us a Message

Tell us about your vehicle and what you need — we'll get back to you as soon as possible.

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