I have an 05 3500 CC Dually with the Duramax and ZF 6 speed. When I first got the truck, the transmission was VERY hard to shift. It was hard to get it to go into gear. Now I have about 700 miles on the truck, the tranny has loosened up some. The only problems are: when the tranny is cold, 3rd gear is VERY hard to engage. After the tranny gets some heat in it, it is OK. 2nd, When shifting into 4th, sometimes (about half of the time) there is a feeling that is kinda the same as the stick feels when you strip a gear. No noise and just for a second, however, the other day, i heard a noise like a gear stripping when I felt this in the stick. My wife didn't hear it, maybe it seemed louder to me cause I could feel it in the stick. Is this a common or normal thing?? Thanks for the help.