hello guys so i went to a dealership and i ended up test driving a 2013 dodge dart Mopar edition. i really enjoyed the comfort of the car when driving it but upon downshifting (engine breaking) a vibration could be heard from eather the dash or back of engine bay? i am curious as to what that may be. the previous owner replaced the clutch and transmission at a shop 2 months back.. wondering is maybe somthing needs to be worn in? or.. in general what everyone might think it may be. theres no vibration feeling just sound when downshifted and engine breaking Only.