Noises During Shifting problems of the 2010 Dodge Avenger

After driving the vehicle for 30-45 a clunking noise begins in the left front, which gets louder the longer the vehicle is driven during one driving period. After parking the vehicle long enough for it to cool down, the problems starts again. Took vehicle to mechanic who said was common problem but need to take to dealer for correct diagnosis - after 3 days the dealer determine rack & pinion needed replaced. I bought this car new & drive 90-95% of the time on the highway. Also, when braking the car shimmies and shifts. They state this is not included in the power train warranty. My previous vehicle was a 2008 Dodge with 110,000 miles on it at trade-in, I drove more in-town driving with it & it never needed any kind of repair.