These Chevy Trucks Are Running Out Of Gas Prematurely (And GM Doesn’t Know Why)
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Chevrolet and its kissing cousin, GMC, are having a problem with some of their heavy-duty full-size pickup trucks that currently defy a solution. The affected models, according to GM Service Bulletin PIT6467A dated February 2026, are model year 2025 and 2026 Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD trucks equipped with the 6.6-liter L8T V8 gasoline-powered engine. According to the bulletin, “Truck runs out of fuel with the fuel gauge indicating there is still fuel in the tank,” and “Fuel gauge defaulting to empty, but there is still fuel in the rear tank.” The bulletin also notes that the SES MIL light can illuminate with no impact on drivability. It lists a possible cause as, “The cause of this condition could be the rear tank is not transferring fuel to the front tank.”
This issue applies specifically to all chassis-cab versions of these heavy-duty trucks with the 6.6-liter V8, which come standard with dual fuel tanks, denoted as RPO code N2N. These trucks have fuel tanks located in front and rear, with a total fuel capacity of 63.5 gallons. The trucks can potentially stall when their fuel gauges read empty, even though there is adequate fuel remaining in the rear tank.
This is not a new problem for the Chevrolet Silverado 3500 HD and the GMC Sierra 3500 HD trucks, made in GM’s historic Flint, Michigan assembly plant. Back in 2024, a similar problem afflicted these trucks, but that time it affected those packing the 6.6-liter Duramax L5P V8 turbo-diesel.
What is General Motors going to do about these Chevy Trucks running out of gas prematurely?
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The answer to this pressing question is — nothing right away. The GM Service Bulletin referenced above provides specific instructions for mechanics seeking quick solutions. It states, “Do not replace any parts at this time. Engineering is currently investigating. The PI (Preliminary Information) will be updated or replaced with a TSB (Technical Service Bulletin) once a determination has been made.” In other words, GM does not really know why this is happening and therefore does not have a solution at this time. It will take GM engineers some time to analyze exactly what is causing the fuel gauge to read empty when there is still gas in one of the tanks, as well as why these trucks stop running even when there is an adequate amount of fuel to keep them moving.
It is likely that the affected Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD trucks, some of which are more reliable than others, will be closely monitored, with their gas tanks kept near the full mark, until the source of the problem is identified. The cause could be a defective part, an assembly defect, a combination of both — or something else entirely.
