So I've got an 05 4runner with 105k on it. Last 2 weeks tranny has acted up. Once from stop light when I hit the gas engine just revved and didn't move, like it was in park. Then just today was doing about 30 mph and went to give it some gas and engine just revved. Slowed down and pull onto a side street and worked just fine. Like it's getting stuck between gears. Any suggestions? Simple tranny fluid change/flush do the trick?