What are the most common GMC Sierra 3500HD problems?
According to Au7o's analysis of 510+ owner reports, the 2008-2008 GMC Sierra 3500HD has 4 documented issues. The most frequently reported are: Transfer case pump rub causing fluid leak and transfer case damage (4WD), Allison 1000 Transmission Control Module and Sensor Failures, Glow plug control module / glow plug circuit faults causing hard cold starts (Duramax). Of these, 2 are rated critical and should be addressed promptly.
Is the GMC Sierra 3500HD reliable?
The 2008-2008 GMC Sierra 3500HD has 4 known issues documented across 510+ owner reports. 2 issues are rated critical: Transfer case pump rub causing fluid leak and transfer case damage (4WD) and Allison 1000 Transmission Control Module and Sensor Failures. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common GMC Sierra 3500HD problems?
Repair costs for known GMC Sierra 3500HD issues range from $180 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Transfer case pump rub causing fluid leak and transfer case damage (4WD), typically costs $450-$2,800 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 2007-2014 GMC Sierra 3500HD Transfer case pump rub causing fluid leak and transfer case damage (4WD)?
On 4WD Sierra 3500HD models with GM transfer cases that use an internal pump, owners report a leak caused by the pump wearing through the magnesium case (commonly called "pump rub"). This can lead to low fluid, chain/bearing damage, and eventual loss of 4WD function. The problem… Repairs typically run $450-$2,800. Severity: high.
What is the 2008-2019 GMC Sierra 3500HD Allison 1000 Transmission Control Module and Sensor Failures?
The Allison 1000 transmission paired with the Duramax diesel in 2008-2015 Sierra 3500HD trucks has a high failure rate for the Transmission Control Module (TCM). A class action suit was filed covering these years. Additional issues include input/output speed sensor failures causi… Repairs typically run $500-$3,500. Severity: high.
What is the 2007-2019 GMC Sierra 3500HD Glow plug control module / glow plug circuit faults causing hard cold starts (Duramax)?
Duramax-equipped Sierra 3500HD owners report hard starting, extended cranking, and rough idle in cold weather due to glow plug system faults. NHTSA complaints and service information commonly involve failed glow plugs, glow plug control module issues, or wiring/connector problems… Repairs typically run $250-$1,200. Severity: medium.
What is the 2007-2019 GMC Sierra 3500HD Blend door actuator failure causing temperature/airflow control problems?
Sierra 3500HD owners report clicking/ticking behind the dash and inability to control cabin temperature due to HVAC blend door or mode door actuator failures. GM service bulletins and owner reports describe stripped actuator gears or actuator motor failures that can leave the tru… Repairs typically run $180-$650. Severity: low.
