ASE-Certified · NAPA Warranty · Diesel Specialists
For nearly five decades, Ironclad Auto has been Bozeman's most trusted name in auto repair — not because we advertise the most, but because we deliver every time.
Founded in 1977 by Walt Greyson, we've outlasted trends, downturns, and dozens of competitors — because we do the job right the first time.
Est. 1977Every qualifying repair is backed by the NAPA AutoCare nationwide warranty — honored at over 17,000 locations across the country.
NAPA AutoCareWe specialize in GM diesel engines and handle all domestic and Asian diesel vehicles — one of the few shops in Bozeman with real diesel depth.
GM Diesel ExpertsDrop off your vehicle and get where you need to go — on us. Our complimentary shuttle means your repair doesn't derail your entire day.
ComplimentaryWe service domestic and Asian vehicles, diesel trucks, and everything in between. If your vehicle needs it, we know how to fix it.
Diagnostics, rebuilds, and full replacements. We read codes and find the real problem — not just the easy one.
Pads, rotors, calipers, and brake fluid — complete brake inspection and repair for peace of mind on Montana roads.
Our specialty. GM diesel expertise and full diesel service for trucks that work as hard as their owners.
Fluid service, filter changes, and full diagnostics for automatic and manual transmissions.
Buying a used vehicle? Let us inspect it first. An hour now can save you thousands later. No pressure, honest findings.
Battery, alternator, starter, and complex wiring diagnostics. Modern vehicles deserve modern diagnostic tools.
Refrigerant recharge, compressor repair, heater core, and HVAC system diagnostics for Montana's extreme seasons.
Conventional, synthetic, and high-mileage oils. Factory-schedule maintenance to keep your warranty valid.
Walt Greyson opened this shop in 1977 with a simple principle: treat every customer the way you'd want your own family treated. Almost five decades later, that hasn't changed — and it shows in every review we receive.
"I've been going to Ironclad Auto for years. As a woman, I always feel respected and never talked down to. They explain everything clearly, never push repairs I don't need, and the work is always done right."
— Verified Google ReviewPhoto report sent directly to your phone
At Ironclad, you'll never wonder why a repair was done or whether you needed it. We believe in showing you, not just telling you.
Our technicians inspect and photograph any issue found — worn parts, leaks, damage — before writing a single estimate.
We walk you through what we found in plain English. No jargon, no pressure. You decide what gets fixed.
Every approved repair is completed by ASE-certified technicians and covered by the NAPA 3-Year/36K warranty.
"I've taken three different vehicles here over the years. They never find problems that don't exist. That kind of honesty is rare and I won't go anywhere else."
"Brought in my '03 Duramax when two other shops said they couldn't diagnose it. Ironclad found the injector issue same day and had me back on the road in 48 hours. These guys know diesel."
"As a woman who knows little about cars, I always dreaded the shop experience. Ironclad is completely different. They explain everything, never make me feel dumb, and I trust every word they say."
"Car started making a terrible noise Monday morning. Called Ironclad, they got me in Tuesday and I had it back by Wednesday afternoon. Fast, fair price, and the shuttle saved my whole week."
Fill out the form and we'll confirm your appointment by phone or email. Questions? Call us at (406) 555-0421.