I just bought my first Ford F-150 4 door 4X4. For the first three months I fell in love with the truck and received a lot of compliments regarding my accessories. About a month ago, I was driving back from a job in Louisiana on a nice smooth two lane hwy when the rear end of the truck started............well hopping as if the wheels were hopping up in the air. It was so bad, I pulled over to see what might be the problem. First I thought I had a tire balance problem so I had the tires balanced and that took most of the vibes out. However now after a total of 18,000 miles, I feel a vibration when starting from dead stop and on occasions it does it driving down the road. I'm worried because it's getting worse. Last night as I was taking it to the local Ford dealer for repair, it shifted HARD into second gear, almost like a pop. This is the part I hate.......the service advisor called me today to say that it needed a shim kit that they would have to order. I don't like the way this is going but I'll wait and see. I'm thinking it's in the drive train (ie. torque converter, transmission, rear end, etc.) Has ANYBODY heard of the 2011 trucks doing this??? This is why I don't buy NEW vehicles!!! It's not the money, it's the bugs that need to be worked out!! Help!!!