Diesel · Craig, CO
Duramax Diesel Repair
LB7 to L5P, with the Allison behind it, we service GM's Duramax for the trucks that work the Yampa Valley.
Average rating
Google reviews
Years, since 1985
Mile warranty
Quick answer
What Duramax problems do you repair?
We repair the common Chevy and GMC Duramax issues, injector and CP4 fuel pump failures, turbo and fuel system problems, EGR and DPF/regen faults, and Allison transmission service, across LB7 through L5P trucks. Accurate diagnosis, quality parts, and pricing well below the dealer.
What's included
- Injector and CP4 / fuel system repair
- Turbo and emissions (EGR/DPF) service
- Allison transmission service
- Preventive maintenance and diagnostics

Built for the Yampa Valley
Duramax-Allison trucks are workhorses for ranching and hauling here. We keep them running strong through hard winters and heavy loads.
Why Chapman's for this
- Free digital inspection with photos
- Transparent pricing, quoted before we start
- Loaner cars, shuttle & pickup
- 5yr / 50,000-mile warranty
What customers say
“Our brakes went out suddenly while we were in town and Chapman's took care of us! We requested some extra work while we were there, which included ordering some specialty parts. They were as fast as they could have been when squeezing us in last minute, and courteous as the day is long. Excellent customer service, keeping us as up to date as possible, not doing work until we approved it, and providing a loaner as we are not local and our truck is our only transport. Our truck is now in tip top shape and worthy to pull our rig again. Highly recommend this shop! Thank you Chapman's!”
Willow W.
3 weeks ago
“Dropped in to check them out and get a competitive quote on repairs. They did a full diagnostic at no charge with service recommendations and costs. Came back the next day for service. They went out of their way to make me feel a valued customer, including a loaner car. Work was done professionally, including a quality control drive before turning the car over to me. Price was very good. Worth the trip.”
Harvey G.
3 months ago
“Just had a great experience at Chapman Automotive and had to share. Cole, Kyle, and the whole team were awesome to work with—super understanding, patient, and most importantly, realistic about what actually needed to be done and what it would cost. No pressure, no upselling, just straight-up honest service. I brought in my diesel truck expecting the worst after getting some pretty high quotes in Steamboat, and they ended up saving me over $3k on the repairs. That kind of honesty and transparency is hard to find. Really appreciate a shop that treats you like a person and not just another invoice. Highly recommend these guys if you want solid work and people you can trust.”
Nathan B.
4 months ago
Frequently asked questions
Yes, fluid service through repair. The Duramax and Allison work as a pair, and we service both under one roof.
We diagnose and repair CP4 and injector failures, including the cleanup the failure can cause downstream, so the fix is complete.
Ready for duramax repair?
Book online in under a minute, or call and talk to a real person. Craig, CO · Yampa Valley.
