I have a FWD 2012 Traverse 1LT earlier this week, upon start up I noticed that I heard a strange sound. I listened as i was driving at high way speeds and noticed the engine was wanting to rev higher into the 4000 or 5000 range. Then one day i turned on the air conditioning and it made a knocking or cranking sound. The traverse has less teh 90000 miles on it and had some transmisson problems around 78000. Other then that it has been kept in near pristen condition mechanic wise. THe oil was always changed aroud teh 50-60% mark. Should i be concerned or is this common for this model. It also is single and not dual exhaust like some models were.