Well y'all I need some help.
I have a 2004 Rubicon here in Japan and I have a vibration at 55+ MPH in the seat. The vibe started after I changed the tires from worn out Maxis Bighorn's to Goodyear Silent Armor's. Since then I have had the tires balances 4 times by 3 different tire shops and the tires replaced by Goodyear (they don't have the silent armor size in Japan so now I have Wrangler ATS's). The vibration was still there.
So I thought the problem may be mechanical. Since then, I have replaced the rear driveshaft, which had a little axial play but not more then a 1/16", rear axle shafts, the passenger side shaft was bent about 0.01, and axle bearings only to jump on the highway and feel the vibration again at 55+ MPH. It didn't seem as bad but it is definitely still there.
My Jeep is not lifted and is mostly stock.
Any help would be most appreciated.