This Preliminary Information communication provides information to the technician about vehicles that may have a concern with a rattle noise at 30 to 40 MPH when the engine is switching between V8 and V4. Technician will need to inspect the drive belt tensioner for a hydraulic fluid leak if the vehicle was built before March 15, 2014. If the tensioner is leaking, it will need to be replaced. If the tensioner is not leaking, disconnect the electronic passive exhaust valves. If the noise changes plug 1 electronic passive exhaust valve in to isolate which valve is the concern. If there is no change replace the belt tensioner.
