Front End Issues @ 45mph or higher

[timgco]

I am running 35" X 18" BFG MT's on my 06 (5200 miles). The tires have around 10,000 on them and have been rotated once on the 04 when I had it. They are wearing fine. (no abnormal wear).

I had them re balanced at the Firestone dealer. They weren't off by much, and than again by the HUMMER dealer and rotated again. They said the tires were almost dead on and the test they did on them said no broken belts. All front end components were tight and the RAncho shocks seemed to be Ok as well. The Fabteck tierods were also check.. again, no issue.

issue #1:
So when you hit 45mph you notice a slight front end shake in the steering column and floor boards. It's the same on both DR SD and PS SD. From 45 mph and higher the shake gets worse. 85mph, the truck shakes badly to the point your hands fall asleep on the steering wheel.

issue 2:
the truck tracks straight when you let go of the wheel below 45mph. When you go above that, the truck wanders back and forth but still tracks straight for the most part. It's like you have to adjust the steering wheel more frequent tahn normal.

So, what so you think? The dealer gets the truck this week.

Ball joint? Ideler arm? Pitman arm? Steering Linkage? Axle?