I just had the same thing happen on my 95 f-150.  Theere was a thumping and the faster I went the worse it got so I took it to the local shop and they said put some new tires on that truck Paul. I thought it was a blown out shock or a ball joint or something. I put a good set of used tires on it and the problem dissappeared. Couldn't believe a bad tire could do so much>
Terry.Atkins@xxxxxxxxxxxxx wrote:  
While my guess it would be a broken   Paul cord in a tire, you probably couldn't see 
it, I have seen bearings with flat spots in them that give off thumping 
noises. 
Terry
From: "Charles Burch" <warlocke@xxxxxxxxx>
To: <BaadAssGremlins@xxxxxxxxxxxxxxx>
Subject: Re: [BaadAssGremlins] weird noise
Date: Wed, 14 Dec 2005
 02:22:13 +0000
        there is somthing in the rear tire but its just a clump of dirt that i know and its not that, its almost constant and faster when speeding up
    ----- Original Message ----- 
      Sent: Tuesday, December 13, 2005 7:26 PM
  Subject: Re: [BaadAssGremlins] weird noise
  
  Bearing don't usually go "thump, thump, thump". Does it remain constant or does it seed up as the car goes faster? Does it only thump when it's rolling?
   
  There may be a busted cord in an old tire causing the thump.
   
   
  Rick