GMC Truck & Duramax Repair in Washington, UT
Sierra 1500, 2500HD and 3500HD, Canyon, AT4 and Denali. Duramax, Allison and suspension work in Washington, Utah.
Sierra HD trucks come in for Duramax maintenance and tow-duty inspections. AT4 and AT4X owners come in for lift work and alignment. Denali owners come in for air-ride diagnosis. All of it happens in one shop in Washington, Utah.
We service trucks, SUVs, Jeeps, Broncos and daily drivers, gas and diesel. If you don't see your vehicle here, call us.
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 paper schedule suggests, because desert fuel stops and dust exposure shorten filter life. Injector balance rates and rail pressure get read on higher-mileage trucks before parts get ordered.
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 share the AFM and DFM lifter pattern with Silverado. 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 run in-house. Heat and dust are hard on air suspension, so the fault gets traced before a compressor goes on the parts order.
AT4 and AT4X trucks take leveling kits, 2 to 4 inch lifts and larger tires. Alignment finishes on the 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. Call with your mileage and we will quote your visit before the work starts.
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 truck work happens under one roof in Washington, Utah.
The same shop services Polaris, Can-Am and Kawasaki side-by-sides — shock rebuilds, clutch 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 both are routine work here. 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 run in-house. Desert heat and dust wear air springs and compressors faster than the factory interval assumes. We trace the fault with live data first, so the part that gets replaced is the part that failed.
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, which is what keeps front tires from wearing on one edge. Alignment finishes on the Hunter HawkEye Elite with a printout.
What GMC problems show up most in Washington and St George?
AFM lifter failure on 5.3L Sierras, air-ride compressor failure on Denali, DEF sensor faults on L5P trucks and front brake heat on 2500HDs towing loaded trailers. These patterns follow the climate and the terrain here. We build the inspection around them rather than reading a generic checklist.
Ready to Get Started?
Call the shop with your year, mileage and what the truck is doing. We book service in Washington, Utah, minutes from St George.