I just bought a 2011 Nitro with 63 miles on it. When the truck heats up and I start to accelerate there is a knocking/clicking sound, sometimes loud sometimes quite, coming from under the car. It goes away after I get up to around 5mph. So the noise is only when I'm dead stopped accelerating to 5mph, then it goes away, and also if I'm in park and very lightly hit the gas it makes the same noise. I brought it to the dealership and the mechanic said all Nitros do it and that it is a valve in the transmission. So I don't believe him and plan on taking it to another dealership. Anyone else have the same noise? Thanks and I'm new. This is my first post. Hopefully this forum will work for me lol!