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
“Stranded with a broken pitman arm, I had it towed in around 1pm. The mechanic stayed late to finish the job so I could get back on the road to California that evening. Above and beyond.”
Brian M.
Verified customer
“So worth the drive from Steamboat. Friendly, efficient service and a comfortable waiting area with WiFi. I won't take my car anywhere else.”
Johanna B.
Steamboat Springs · Verified customer
“Once I found Chapman's in Craig, I haven't gone anywhere else. Free, timely inspection and they even have an in-house Mini Cooper specialist. Worth the drive from Hayden.”
Brian H.
Hayden · Verified customer
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.
