Diesel Engines Repair & Maintenance

Expert Service for Duramax LB7, LBZ & Cummins Diesel Engines

At MJ’s Mobile Fleet LLC, we specialize in the repair, diagnostics, and maintenance of diesel engines commonly found in ranch trucks, commercial fleets, and ground support equipment. With over 30 years of experience, our family-owned, bilingual team provides expert service on the following engines:

• Duramax LB7 (2001–2004)
   
• Duramax LBZ (2006–2007)
   
• Cummins 5.9L, 6.7L, and ISB models
   

These engines are known for their power, reliability, and longevity when properly maintained. We help keep them running strong with comprehensive diagnostics and repairs.

• In-shop injector and fuel system repairs
   
• High-pressure fuel pump replacement and repairs
   
• Turbocharger diagnostics and servicing
   
• Glow plug and grid heater replacement
   
• Diesel Particulate Filter (DPF) replacement and emission system maintenance
   
• Engine compression testing and leak diagnosis
   
• Electrical and sensor troubleshooting
   
• Check engine light diagnosis and resolution
   
• Preventive maintenance programs for fleets
   

• All major repairs are completed at our fully equipped Stockton, CA shop to ensure quality and safety
   
• Extensive experience with Duramax LB7 and LBZ engines, as well as a wide range of Cummins diesel models
   
• Trusted by ranchers, fleet operators, fuel distributors, and airport ground support clients
   

We proudly serve customers across Stockton, Sacramento, San Jose, Oakland, Fresno, McClellan, San Francisco, Fallon (NV), and the surrounding regions.

Keep your diesel engine running at peak performance. Contact MJ’s Mobile Fleet LLC at (408) 661-1489 to schedule a in-shop repair appointment.