Vibration around 35 MPH??

[Josh.Larsen]

So for the past 3 months I've been noticing a vibration when cruising around 35 MPH and it may be getting worse. I have a 2005 1500 with a 4.7 4x4 single cab short box.
It only happens when I slightly press the gas to maintain speed. To describe it the whole cab "wobbles" or "shakes" not violently but enough to notice. If I depress the gas to slow down it will quit and if I press the gas down enough for the Rpm to rise then it quits. I bought the truck 4 months ago and the only thing that I see underneath is the pinion seal is leaking which I'm planning on replacing.

The truck has 107,*** miles on it
The rear diff fluid was super clean when I checked it and the front was just changed.

If anyone has any clue or experience it'll be very well appreciated.
Thanks

 

[rhoadsrocker]

I'd say a slightly unbalanced wheel that levels out a bit when speed picks up. Or a bearing/hub assembly depending on what type of vibration it is. I had a slight vibration that didn't shake the hell out of my truck but was noticable and started at about 35mph as well. Turned out to be the hub assembly. If it stops when you turn while going about 40 I'd say that's probably what it is.

 

[usaf2006]

Mine does something like that. But mine is a hemi. When I cruise around 35, if I let off the gas it sounds like my exhaust is what's doing it, making me think it's a weird spot for my MDS to kick in.