2009 outback h6, recently when shifting there is a hesitation and lag. There is a clear jerk when going from one gear to another, on upshifting. This only happens a couple of times a day. The car is driven gently on city streets and highways. This is not limited to a particular gear as far as I can tell. what do i look for and how much should i worry. The car has 90k miles and recently was serviced at the dealer but did not have a transmission fluid flush or any transmission work done.