Peterbilt Truck Repair in Austin, TX

Peterbilt service at an independent Austin shop

A Peterbilt down is money not moving, so the work has to be right the first time. We handle PACCAR MX and Cummins power, the air systems, and the front-end and suspension work that keeps a long-nose tracking straight — with a shop full of lifts, alignment equipment, and parts instead of a service van.

Peterbilt models and drivetrains we service

• 389 — The classic long-nose, and the one owners keep forever — steering, front axle and suspension work, and engine service.
• 379 — The predecessor to the 389 and still very much on the road. Pre-emissions examples avoid the aftertreatment problems entirely.
• 579 — The current highway tractor — PACCAR MX-13 or Cummins X15, with full modern aftertreatment.
• 567 — Vocational: dumps, mixers, and heavy construction work, where short cycles are hard on emissions systems.
• 520 & 220 — Refuse and medium-duty cabovers working routes rather than highways.
• 337, 348 & 537 — Medium and heavy vocational chassis with PACCAR PX-7 and PX-9 power — the Cummins B6.7 and L9 under PACCAR badging.
• PACCAR MX-11 & MX-13 — Diagnostics, aftertreatment faults, EGR, turbo, and engine repair.
• Cummins-powered Petes — ISX and X15 service — fuel systems, turbos, and emissions. Still the preferred spec for a lot of owner-operators.
• Older Cat & Detroit power — C15, C13, and Series 60 trucks that are still working. We do not tell you to replace a truck that runs.

What we see fail on Peterbilt

• Aftertreatment derates — DPF loading, DEF quality and dosing faults, and SCR problems that shut a truck down mid-haul. See DPF cleaning and DEF & SCR.
• Air system leaks — Slow build, dragging brakes, and leaks that show up on a DOT inspection at the worst time.
• Front-end wear — Kingpins, tie rods, and steering slop that eats steer tires and wanders on the interstate — the classic long-nose complaint.
• Steer tire wear — Almost never the tires. Feathered or one-sided wear points at alignment or front-end components, and new rubber on a bad front end wears out just as fast.
• Suspension and alignment — Air bags, ride height, and alignment on both the truck and what it pulls.
• Electrical and sensor faults — Intermittent faults chased with live data rather than replaced on a hunch.
• EGR and turbo on MX engines — Soot loading, sticking vanes, and coolers that leak — worth testing before condemning an expensive part.

Peterbilt work we handle

• Engine diagnostics and repair on PACCAR MX and Cummins power
• Air brake service, including full brake jobs and air-system leaks
• Front-end, steering, kingpin, and suspension work
• Heavy-duty alignment for tractors and trailers
• Annual DOT/FMCSA inspections
• Aftertreatment work — DPF cleaning, DEF systems, and derate faults

Keeping a Peterbilt on the road

• Front-end and kingpin inspection — The single highest-value item on a long-nose truck. Caught early it is a bushing; ignored it is steer tires plus the front end anyway.
• Alignment on an interval — Not just when something feels wrong — steer tires are expensive enough that alignment pays for itself.
• Fuel filters — MX and X15 injection both run at pressures where dirty fuel becomes a four-figure repair.
• DPF cleaning before the derate — Ash accumulates no matter how well the truck runs. Scheduled beats stranded.
• Air dryer cartridge — Cheap and routinely skipped, and the reason moisture ends up in the air system.
• Wheel ends and brakes — Checked at PM rather than at roadside — brakes are the top out-of-service category every year.

Intervals depend on how the truck is worked, not on the odometer alone — see diesel truck maintenance schedules for how we set them, or fleet preventive maintenance if you run several.

The independent alternative to the dealer

Peterbilt service usually means the dealer, and for an open recall or a factory warranty claim that is where the truck belongs. Outside of that, an independent shop is generally faster to get into and easier to talk to — which matters when the truck is the business. We run full-size bays with lifts, alignment equipment, and parts on the shelf, so we can do a real front-end job or an aftertreatment repair rather than diagnosing it and sending you elsewhere. For an owner-operator that also means dealing with the person who actually worked on your truck, and being told plainly when a job genuinely belongs at the dealer.

Modern Diesel is an independent, Christian, veteran-owned shop — we service Peterbilt trucks but are not a dealer or affiliated with the manufacturer. Warranty coverage on our work is set with your service advisor at the time of service.

Related services

• heavy-duty parts & repair
• DOT inspections
• air brake service
• heavy-duty alignment
• DPF cleaning & aftertreatment
• DEF & SCR repair
• trailer repair

Other makes we service

Kenworth · Freightliner · Volvo · Mack · International · Isuzu · Hino

Bring it to the shop

We work on Peterbilt at our shop at 2900 N FM 973, Austin, TX 78725, serving the Greater Austin Area (Travis, Bastrop, Williamson, Hays) — Austin, Del Valle, Manor, Elgin, Pflugerville, Round Rock, and the surrounding counties. Call 512-717-2777 and tell us what it's doing, or send us the details and we'll get back to you.

Common questions

Can you do a DOT inspection on my Peterbilt?

Yes. We perform annual DOT/FMCSA inspections on trucks and trailers, and if something fails we can usually repair it in the same visit instead of sending you somewhere else and starting over.

My Peterbilt is in a derate from the aftertreatment. Can you clear it?

We diagnose why it derated — DPF loading, DEF quality or dosing, SCR efficiency, or a sensor — and repair the cause. Clearing a code without fixing what caused it only means the truck derates again, usually somewhere less convenient.

Do you have bays big enough for a long-nose truck?

Yes. Our shop at 2900 N FM 973 in Austin is set up for full-size trucks with lifts, alignment equipment, and parts on the shelf — which is what makes it possible to do big jobs that a mobile service van cannot.

Do I have to take a Peterbilt to the dealer?

No. Diagnostics, engine and aftertreatment work, air brakes, front-end and alignment, and DOT inspections are all independent-shop work. The dealer is the right call for open recalls, factory warranty claims, and certain proprietary programming — we will say so up front when that is genuinely the answer rather than keeping the truck while we find out.

Is a PACCAR MX-13 the same as a Cummins?

No — the MX-13 and MX-11 are PACCAR’s own engines, built on DAF architecture. What does carry a Cummins underneath is the medium-duty PACCAR badging: PX-7 is the Cummins B6.7 and PX-9 is the L9. So a 337 or 348 with a PX engine is effectively a Cummins truck, while a 579 with an MX-13 is not. Send the VIN and we will confirm before you come in.

My steer tires are wearing out fast on my 389. What is wrong?

Almost never the tires. Rapid or uneven steer wear on a long-nose points at alignment or front-end components — kingpins, tie rod ends, or a bent part. Replacing the tires without fixing the cause just buys another set at the same interval. We measure the alignment and check the front end before selling you rubber.

Can you work on an older pre-emissions Pete?

Yes, and gladly. Older 379s and pre-2007 trucks with Cat, Detroit, or Cummins power avoid aftertreatment problems entirely and are worth keeping running. We do engine work, air systems, front ends, and inspections on them — we are not going to tell you to buy a new truck because yours is old.