Braking Vibration!

[Rollin' Heavy]

Ok, here I go. Hopefully this makes sense. I drive a 2005 2500 4x4 with only 45,185 miles on it. I bought the rig Aug 2008 with only 41,400 miles on it. I have a company truck so the Dodge is more like a BEAUTIFUL lawn ordiment.

Ok, it all started after I was in 4 wheel drive, but I am just now figuring it out. Anyways, I got a vibration while driving around 65 or so. But it is really bad when I let off the accelerator. But when I accelerate, the vibration goes away mostly.

But here recently, I have noticed that when I brake, I feel a vibration and hear a sound that is like a card in bicycle spokes. I have to put a little more pedal pressure than normal but not much more.

I checked the wheel bearings, pinion bearing, and the driveline bearings. They do not appear to be bad.

Tonight thought, when I put the truck into 4H and tried to stop the vibration was not there. I tried this many times with NO problems. Than I put the truck back into 2H and the vibration is back. The 4 wheel drive little in the dash is not coming on. Would this be the problem?

I need all the help I can get. I just found out that the 7 year/70K mille warranty was not transfered from the dealer I bought the truck at. I dont mind spending money, but I dont have money to throw at them to find the problem.