My brother has a 04 2wd 5.9l pickup 60,000 miles with the nv4500 transmission. Since he bought the truck it had a rattling noise in 5th gear not very loud but noticable. He brought it to the dealer and got them replace it with a rebuilt one under warranty. About a month later same noise came back and it isn't as tight shifting as it was at first. Now they are saying that it is common in these transmission to make the noise. They said that we are hearing the "fingers floating" and it isn't a problem. Is this a common noise or are they full of it?