Lemon-lawed GMC Sierra 2500 HD Denali at 8,000 miles due to transmission troubles, yet opted for a 2025 Sierra HD AT4 model acquisition.
In the automotive world, brand loyalty often runs deep, but recent powertrain issues with the 2024 and 2025 GMC Sierra Denali HD and Sierra 1500 trucks are testing that loyalty.
Todd Fedde is currently going through the Lemon Law process for his 2025 Ultimate 2500, which has spent 55 days in the shop due to stalling out and an infotainment center lockup. Another user, Brandon Perault, admitted that Nico's situation made him second-guess his own plans to buy a GM truck, specifically due to the valve body issue.
Nico, too, had a lemon law experience with a 2024 GMC Sierra Denali HD, which had only 8,000 miles on the odometer before experiencing a drivetrain-related failure. Despite this, Nico replaced the lemon lawed truck with a 2025 GMC AT4 HD.
The valve body issue has become a hot topic among GM truck owners, with some trucks waiting for weeks on parts. The failure was caused by a manufacturing error in the transmission cooler line that drained all the fluid and led to the transmission burning up. This issue has led some members of the "GMC Denali Diesel Duramax" group on Facebook to express concerns about GM's quality and reliability.
Common issues reported by owners of these trucks include Diesel 3.0 Duramax engine problems, transmission control valve body failures, a rare electrical issue, and a rear axle lubrication issue in some 2025 Sierra 1500 units.
GM has acknowledged these issues and is offering extended warranties or repair programs. For instance, they are providing repair coverage for transmission valve body failures via Special Coverage N242454441, though supply chain delays linger. They are also issuing Customer Satisfaction Programs to replace faulty or durability-compromised parts like the 2025 rear axle assemblies at no cost to owners.
However, some owners are experiencing extended wait times due to supply chain constraints affecting part availability. Aram Krajekian, an automotive journalist who covers the evolving automotive landscape, encourages affected owners to schedule prompt dealer service appointments upon receiving notifications.
Despite these challenges, some truck owners are willing to forgive issues with their vehicles due to brand loyalty. However, as examples like Nico's early-life failure in a 2024 GMC Sierra Denali HD (at just 8,000 miles) and another 2024 Silverado 3500HD with transmission issues at 21,000 miles, demonstrate, this loyalty is being tested more than ever.
It remains to be seen how GM will address these issues and regain the trust of their loyal customer base. For updates on this and other news about cars, follow Aram Krajekian on X and LinkedIn. As for the truck in question, it has not yet been re-purchased by GM. Nico, however, chose to return to the Sierra lineup due to the combination of luxury and familiarity that GMC's heavy-duty trucks deliver.
The financial impact of these transmission issues on GM might be significant, given the extensive repairs needed and potential recalls.
Industry experts suggest that the transportation sector, particularly within the automotive industry, will closely monitor GM's handling of these issues to assess their long-term impact on consumer trust and sales.
