I have an 07 Tundra SR5, TRD with 500 miles. I am getting a vibration within 1-2 miles from start-up from cold at 35-40 mph. Not consistent or steady. Feels like going over small washboards and only last a few seconds. Also feel the same thing for just a moment during a 6th to 5th upshift using cruise. I suspected u-joint and took to the dealer. They drove truck over 20 miles during two attempts to duplicate and could not. They called Toyota tech hotline and reported/asked about this, but no answers were there. They told me to keep driving and see if it got worse. Anyboby experiencing similar condition?