We Bought a new 2012 dodge journey RT. When traveling about 70 - 80 km/h in top gear the revs seem to fluctuate for about 10 seconds between 1500- 2000 revs. Wondering if there's a problem with the torque converter? Also when traveling and the car is changes up to 6, the car hesitates and shutters a little. Everytime we start the car and take off theres a loud knock that comes from the front end. We've been told that it is the abs activating but it's getting louder. Any help would great.