Is it a vibration or a thump? I know I have a light thump from my driveshaft due to the slip joint design. Supposedly, greasing the fitting on the driveshaft will fix it for about thirty days. If its a vibration, I'm not sure what it would be.
-2004 Ford F150 Lariat Scab w/ 5.4l
-2005 Chevrolet Corvette M6
-1997 Pontiac TransAm M6 w/custom heads, custom cam, moser w/4.10's and lots of other fast mods