I bought my 2006 QCSB Hemi on July 18th. I love it so far but when I'm on the highway it feels like I'm going down a rumble strip. Sometimes it's very slight but other times everything in the truck rattles. At first I thought it was because they just rotated the tires and they looked like they had never been done before but 2 months later it hasnt gotten any better, if not worse. I have a 90 day drivetrain warranty, I would have gone sooner but I'm a full time student and I work 40 hours a week.

PS
This is my first IFS truck and when I hit a bump it gets a little swirly, dunno if this is normal.

 

It's probably balancing, either get the wheels balanced or try swapping the wheels back to where they were originally and see if it goes, also does the vibration always occur in the same speed range?

Hitting bumps can get a bit hairy, mine does the same, feels like it's trying to side step, although from what people on here say it seems to be the stock shocks aren't man enough.

 

Rims are out of balance (or you hit a curb and bent one) or the shocks are gone. Those would be my bets however both of which are NOT part of your drivetrain warranty though.