- GM faces a new lawsuit over allegedly leaking rear sliding windows.
- Complaint targets 2019-2020 Chevrolet Silverado and GMC Sierra trucks.
- A long-running and often updated GM service bulletin may bolster owners’ claims.
Trucks are supposed to be tough. They’re supposed to stand up to the harshest environments, battle the elements, and be all-around rugged. According to several GMC and Chevrolet owners, their pickups can’t handle some rain without letting it into the cabin.
A new California class action alleges that rear sliding windows installed in certain Chevrolet and GMC pickups allow water to enter the cab, potentially damaging electronics, interior trim, and creating conditions for mold growth. More importantly, the suit argues GM knew about the defect long before many owners discovered it themselves.
One Owner’s $1,000 Surprise
2019 GMC Sierra
Filed by California resident Filiberto Loza Gonzalez, the lawsuit covers certain 2019 and 2020 Chevrolet Silverado and GMC Sierra models equipped with power-sliding rear windows. According to filing seen by Car Complaints, Gonzalez discovered water intrusion in his 2019 GMC Sierra 1500 while washing the truck. Although a dealership reportedly verified the issue and performed repairs, he alleges he was left with a bill exceeding $1,000.
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Gonzalez doesn’t seem to be alone either. Forum posters and other social media users report the same sort of problem. One on GM-Trucks.com writes “GM will try to put a bandage on the window cracks in the form of sealant instead of actually replacing the defective window. Many of the people in the forums report that the sealant does not last as was the case with mine. If you are unlucky enough to fall outside of warranty when the sealant fails, GM will not cover anything without a fight.”
The Bulletin GM Kept Revising
2019-2020 Chevrolet Silverado
Over the years, GM appeared to know about the problem and continually updated a technical service bulletin in an effort to remedy the issue. That effort now appears to be a lynchpin in the case. According to Technical Service Bulletin 18-NA-383, technicians were instructed to inspect for cracking in the rear sliding window’s plastic upper rail guide, a condition that could allow water to bypass the urethane seal and enter the vehicle.
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GM’s prescribed repair involved removing the rear roof spoiler and applying seam sealer across the top of the window assembly. The document further notes that if the repair failed and the vehicle returned with the same complaint, dealers should replace the entire rear sliding window assembly.
That last detail could prove important. The lawsuit claims GM concealed a defect involving substandard materials and continued selling affected trucks despite knowing about the issue. The fact that the bulletin has gone through numerous revisions over the years may become a point of contention. The March 2023 version included in court filings is labeled Version 13 and shows a revision history stretching back to the bulletin’s original release in early 2019.
The proposed class includes owners and lessees in California of certain 2019 and 2020 Silverado and Sierra 1500, 2500HD, and 3500HD models. For now, the allegations remain unproven, and GM has not been found liable. That said, plenty of affected owners might want to pay close attention to what happens from here.
