Some owners of 2011-2012 Chevy Silverado and GMC Sierra vehicles (all with crew or extra cab) may complain about a rattle noise at the rear of the cab while driving over sharp bumps.
The condition may be caused by the upper seat back hook isolator not fully engaging in the seat back mounting hook.
- Remove the rear seat assembly (it is not necessary to disconnect the seat belt or to completely remove the seat from the vehicle).
- Remove the isolator from the seat frame hook by disengaging the locking tabs.
- Reinstall the isolator into the seat mount hook, remove the remaining adhesive protective film and firmly press the isolators into position.
- Reinstall the isolator retainers.
- Repeat the above steps on all three isolators.
- Reinstall the rear seat assembly.