Just to be clear, this is all the way the shift "feels" and not "sounds," correct? As long as you aren't hearing any noise, I think what you are experiencing is temperamental shifting as your engine becomes warmer. Do a search on shifting and it will come up. it's a common Tdub characteristic. Mine does it and and it has only 750 miles on it. The fix, so some say, is a higher viscosity oil, or just put up with it.