2001 Durango, 4.7, 2wd, 178k miles. Just changed the fluid about 5k miles ago. No problems until recently. Under more than half throttle, the engine will rev, sit at whatever rpm (say 3k) for about 5 seconds or so, then shift to the next gear. If I'm easy on the gas, it shifts no problem. Fluid is full, doesn't smell funny at all. It shifts funny into all gears, but it seems worse into 3rd and 4th. No check engine light or od light. Any thoughts? Thanks!