Owners of 2014-2015 Cadillac CTS sedans, XTS or ATS vehicles equipped with a 3.6L twin turbo engine might comment on a brief rattle or tick when revving the engine when the transmission is in park or neutral.
Note location of bracket to transmission fasteners.
The same rattle or tick can sometimes be heard at the beginning or end of a vehicle acceleration while in drive. This might be due to the turbocharger wastegate. The condition might be caused by loose converter bracket nuts or might be a normal characteristic of the turbo wastegate.Inspect the M8 nuts that secure the catalytic converters to the exhaust bracket. If the nuts are loose, replace them with new torque-prevailing nuts, P/N 11546441.