General Motors has issued a customer satisfaction program for certain examples of the 2020 and 2021 model-year Chevy Silverado HD and GMC Sierra HD over issues related to the transmission oil cooler jumper lines.
The problem: certain 2020-2021 model-year Chevy Silverado HD and GMC Sierra HD trucks may have a condition in which the transmission oil cooler jumper line has a leak at the crimp.
The hazards: while this problem poses no direct safety hazard to the driver or vehicle occupants, owners will still want to bring their vehicle in for repairs, as the problem may result in fluid leaks that could cause further transmission troubles.
The fix: GM dealers will be instructed to replace the transmission cooler inlet and outlet pipe and also the jumper line. They will also fill the vehicle with new Dexron V transmission fluid.
Affected components: transmission oil cooler jumper line, transmission oil cooler inlet and outlet line assembly.
Number of affected vehicles: it’s currently not clear how many vehicles may have this condition. This problem only affects Chevy Silverado HD and GMC Sierra HD trucks equipped with the gasoline 6.6L L8T V8 engine and not the optional Duramax 6.6L L5P V8 turbodiesel.
Next steps: owners of affected Chevy Silverado or GMC Sierra trucks will most likely be instructed to make an appointment with their dealership to have the transmission cooler lines inspected and replaced. Owners with additional questions or concerns can also reach out to Chevy or GMC directly using the contact information included below.
- GM Customer Satisfaction Program number: N212324960, N212329461
- Chevrolet Customer Service: 1-800-222-1020
- GMC Customer Service: 1-800-462-8782