I have a 2006 mercury mountaineer that has been operating fantastically for the past year. Out of nowhere it seems to randomly get stuck around 3rd gear, engine revs to 5-7krpm without shifting. If i slow down it seems to do the trick or if I immediately park and turn it off on and back on it works fine. The wrench light comes on for about 20-30 secs then disappears. It's a 6 cylinder luxury edition, any ideas guys?