Hi Duc, if it makes you feel any better, my 2006 4.4 has been having the same issue for the past 15,000 miles. It now has 107K miles on it. I too was having a hard shift between 1st and 2nd. 30K miles ago, I had the tranny oil changed. Helped a little but not much. About 2 months ago I had a German car specialist simply reprogram the transmission computer (specifically the tranny). Problem solved. Shifts beautifully smooth now in low gears; however, 5th gear still doing the same lurching when cruising at highway speeds. Not sure if I should invest in a repair right now as it doesn't seem to have worsened over the last 15000 miles.