The Chevy Silverado Diesel and GMC Sierra Diesel are known for their power, reliability, and towing capabilities. However, like all modern diesel trucks, they require diligent maintenance to stay in peak condition. With advanced emissions systems, turbocharged engines, and electronic controls, these trucks can develop issues if not properly maintained.
At Branch Automotive, we specialize in Chevy Silverado and GMC Sierra diesel repair in Littleton, CO, serving Highlands Ranch, CO, and the surrounding areas. Our expert technicians help truck owners avoid costly breakdowns by addressing problems early and performing preventative maintenance.
Understanding the most common Duramax diesel engine issues and taking proactive steps will keep your Silverado or Sierra running strong for years to come.
Common Chevy Silverado & GMC Sierra Diesel Problems
1. DEF Quality Issues (It’s Rarely the DEF Itself)
Many Silverado and Sierra diesel owners experience Diesel Exhaust Fluid (DEF) quality warnings, but in most cases, the problem isn’t the DEF itself. Instead, the issue is often due to sensor malfunctions, injector failures, or crystallization within the system.
How to Prevent DEF Problems:
- Use API-certified DEF and store it properly to prevent contamination.
- Avoid overfilling the DEF tank to prevent crystallization, which can clog the system.
- If a “Poor DEF Quality” warning appears, have the system diagnosed before it leads to power reduction.
At Branch Automotive, we have the specialized tools to properly diagnose DEF system problems, helping Silverado and Sierra owners avoid unnecessary part replacements and costly downtime.
2. Aftertreatment System Problems
In recent model years, GM redesigned the aftertreatment system in the Silverado and Sierra Diesel, making components smaller and requiring more frequent regenerations to clean the Diesel Particulate Filter (DPF). If the system becomes clogged, it can lead to reduced fuel economy, loss of power, and expensive repairs.
How to Maintain the Aftertreatment System:
- Take longer highway drives when possible to allow proper DPF regeneration.
- Avoid excessive idling, which leads to soot buildup in the filter.
- Use synthetic engine oil in 2017 and newer models to protect the system.
If your truck is experiencing frequent regeneration cycles or reduced power, an inspection at Branch Automotive can help prevent a full DPF replacement, which is one of the most expensive emissions-related repairs.
3. Cold-Weather Starting Issues (2017+ Models Require Synthetic Oil)
For 2017 and newer Silverado and Sierra Diesel models, synthetic engine oil is required for cold-starting performance and to protect the aftertreatment system. Using the wrong oil can cause hard starts, increased engine wear, and emissions system failures.
How to Prevent Cold-Start Problems:
- Use synthetic engine oil to maintain proper lubrication in cold temperatures.
- Test glow plugs and batteries before winter to ensure they are functioning properly.
- Consider using a block heater in freezing temperatures to improve cold starts.
At Branch Automotive, we help Silverado and Sierra owners in Littleton and Highlands Ranch, CO, prepare for winter with seasonal maintenance and inspections.
Other Common Silverado & Sierra Diesel Problems
4. Fuel Injector Failure
Fuel injectors on Duramax engines can develop clogs or leaks, leading to hard starts, reduced fuel economy, and rough idling.
Preventative Steps:
- Change the fuel filter every 15,000 miles to protect the injection system.
- Use high-quality diesel fuel with additives to reduce carbon buildup.
- If you notice misfires or power loss, schedule a Silverado & Sierra diesel repair in Littleton at Branch Automotive before the issue worsens.
5. Turbocharger Issues
The turbocharger is essential for performance, but oil starvation, excessive heat, and carbon buildup can lead to turbo failure over time.
Preventative Steps:
- Change the engine oil every 5,000 miles to keep the turbo properly lubricated.
- Avoid excessive idling, which leads to carbon buildup in the turbocharger.
- Have your turbo inspected if you notice power loss, excessive smoke, or a whining noise.
6. Transmission Problems (Allison 1000 & 10-Speed)
The Allison 1000 and 10-speed automatic transmissions in Silverado and Sierra diesels are built for heavy-duty use, but they can develop shifting problems, overheating, and slipping gears.
Preventative Steps:
- Change the transmission fluid and filter every 50,000 miles.
- If you tow frequently, install a transmission cooler to prevent overheating.
- If you experience delayed shifting or rough gear engagement, schedule a Silverado & Sierra transmission service in Littleton before the problem worsens.
Branch Automotive’s Philosophy on Diesel Maintenance
At Branch Automotive, we believe in one simple rule: Don’t ignore problems.
Modern diesel trucks constantly monitor their own performance, but that doesn’t mean they can go without maintenance. Keeping up with preventative services ensures reliability, performance, and compliance with emissions standards.
Key Maintenance Services for Your Chevy Silverado & GMC Sierra Diesel
- Oil Changes – Every 5,000 miles using synthetic oil to protect the aftertreatment system.
- Fuel System Care – Regular fuel filter replacements prevent injector damage.
- DEF System Maintenance – Use only high-quality DEF and prevent crystallization.
- Brake & Alignment Inspections – Prevents uneven wear and handling issues.
- Transmission Service – Routine fluid changes and inspections help prevent failures.
- Differential & Transfer Case Service – Keeps four-wheel drive systems functioning properly.
Why Choose Branch Automotive?
At Branch Automotive, we specialize in Chevy Silverado and GMC Sierra diesel repair in Littleton, CO, and Highlands Ranch, CO. Our team consists of:
- ASE Master Technicians
- Factory-trained GM specialists
- One of the few ASE World Class Technicians in the country
What Makes Us Different?
- Certified Diesel Emission Testing Facility – One of the few in Colorado.
- Chassis Dynamometer Testing – Pinpoints performance and drivability issues.
- Factory Scan Tools & Software – GM-level diagnostics for accurate repairs.
- Nationwide Warranty – Most repairs are covered by a 2-year/24,000-mile warranty.
Schedule Your Silverado & Sierra Diesel Repair Today!
If you need routine maintenance or expert diesel repairs, Branch Automotive is ready to help.
Visit us at: 6030 E County Line Road, Littleton, CO 80126
Call us today: (303) 771-2224
Schedule online at: Branch Automotive
Your Chevy Silverado & GMC Sierra Diesel are built for performance and reliability—keep them running at their best with expert service from Branch Automotive.
