hello, i am new here and have a question about my new truck. i have a 2010 frontier se 4x4 cc. it has 4,000mi. i hear a knocking or clumping noise from the rear or middle of the truck when slowing to a stop. it is a fast pace knock but gets slower as the truck slows. it sounds like a u joint to me. this is my first nissan so im wondering if this is normal. does anyone here have the same problem? any ideas on what this mite be would be a big help. thanks