GMC Truck & Duramax Repair in Washington, UT
Professional Sierra 1500, 2500HD and 3500HD, Canyon, Yukon, AT4 and Denali repair, including Duramax, Allison and suspension work, in Washington, Utah.
MST Motorsports credentials
- ASE Master Certified Technicians
- Hunter HawkEye Elite Alignment
- In-House Shock Rebuilds
- 80+ Years Combined Experience
- Gas & Diesel
- Family-Owned in Washington Since 2020
MST Motorsports provides professional GMC truck and SUV repair in Washington, Utah, for the Sierra, Canyon and Yukon. That covers Duramax maintenance and tow-duty inspections on Sierra HD, lift work and alignment on AT4 and AT4X trucks, and air-ride diagnosis on Denali models. Our factory-trained, certified technicians have more than 80 years of combined experience, and qualifying repairs are backed by our 36-month/36,000-mile nationwide warranty.
We service trucks, SUVs, Jeeps, Broncos and daily drivers, gas and diesel, from Ford, Chevrolet, GMC, Ram, Toyota, Honda and Nissan. If your vehicle is not listed here, call (435) 256-8899.
Platforms We Service
Suspension and lift work runs through truck services, diesel work through diesel repair, and ride-height correction through alignment service.
6.6L Duramax and Allison Work
Sierra HD shares the L5P Duramax and Allison 10-speed with Silverado HD, and the service list matches: engine oil, fuel filter service, DEF diagnostics, Allison fluid, transfer case and both differentials.
Fuel filtration matters more here than the printed schedule suggests, because desert fuel stops and dust exposure shorten filter life, and injector balance rates and rail pressure are read on higher-mileage trucks before parts are recommended.
EGR cooler condition, DPF soot loading and regen history come off the scan tool during a diesel visit. Cooling system pressure testing is part of the service on any truck that tows.
Gas Sierras and Yukons share the AFM and DFM lifter pattern with Silverado, and compression testing and live data come first so a teardown starts with a known cause.
Air Ride Lift and Alignment
Denali Ultimate air-ride diagnosis, compressor service and ride-height sensor calibration are performed in-house, and because heat and dust are hard on air suspension, the fault is traced before a compressor is recommended.
AT4 and AT4X trucks take leveling kits, 2 to 4 inch lifts and larger tires, and alignment finishes on the top-of-the-line Hunter HawkEye Elite with caster and tie rod correction for the new ride height.
Maintenance Intervals
5,000 to 7,500 miles
Oil and filter to Duramax or gas specification, tire rotation, courtesy inspection with photos and video.
15,000 miles
Duramax fuel filter service, engine air filter, cabin filter, DEF quality check, transfer case fluid inspection.
30,000 miles
Allison 10-speed fluid and filter, brake fluid flush, front and rear differential fluid, coolant condition check.
60,000 miles
Driveline fluids replaced, EGR and intake service on diesel, spark plugs on gas V8, front axle service on 4x4.
Air suspension trucks
Ride height sensors, compressor duty cycle and air spring condition inspected at each major service on Denali models.
These intervals reflect Sierra trucks working in Washington County heat and tow duty. , or call or text (435) 256-8899 with your mileage.
GM's published normal and severe-duty figures for the Duramax and Allison are laid out in our Duramax and Allison service interval article.
What We See in Southern Utah
Serving Washington, St George and Hurricane, plus Ivins, Santa Clara, La Verkin and Leeds. Pricing depends on the platform and the mileage, so call for your vehicle.
Book Your Service
Repair, maintenance, lift and alignment in one shop in Washington, Utah.
Side-by-side and UTV service at our Washington, Utah location.
Polaris, Can-Am and Kawasaki side-by-side service, including in-house shock rebuilds, clutch and CVT work and suspension.
Side-by-side and UTV serviceFrequently Asked Questions
Do you service the L5P Duramax in a Sierra HD?
Yes. Sierra 2500HD and 3500HD share the L5P Duramax and Allison 10-speed with Silverado HD, and service covers engine oil, fuel filter service, DEF diagnostics, transmission fluid, transfer case and both differentials. Heat and towing put most local Sierra HDs on the severe-duty schedule.
Can you diagnose Denali air-ride suspension?
Yes. Air-ride diagnosis, compressor service, ride-height sensor calibration and shock replacement are performed in-house. Desert heat and dust wear air springs and compressors faster than the factory interval assumes, so our technicians trace the fault with live data before replacing a part.
Do you lift and align AT4 and AT4X Sierras?
Yes. Leveling kits, 2 to 4 inch lifts and larger tire packages are frequent work on AT4 and AT4X trucks. Factory geometry needs caster and tie rod correction once ride height changes, and alignment finishes on the top-of-the-line Hunter HawkEye Elite.
What GMC problems show up most in Washington and St George?
AFM lifter failure on 5.3L Sierras, air-ride compressor failure on Denali models, DEF sensor faults on L5P trucks and front brake heat on 2500HDs towing loaded trailers. These patterns follow the climate and terrain here, and our inspections are built around them.
Book Service
Call the shop with your year, mileage and what the truck is doing. We book service in Washington, Utah, minutes from St George.