I have a bad vibratuion in my 03 ranger at 70 through 90 mph I had new tires put on and balenced twice also aligned. i pulled rear end cover off did bearings and seals even though it all seemed good and there was no unusual wear on gears. has new u joints and it was still there when i removed the frount drive shaft. it is in the rear of the vehical because i jacked it up and ran it up to speed i remove the tires and ran it up agin to see if it was in the tires and it is still there. the drive shaft was balenced and it seemed the vibration moved up in speed it was at about 60 mph the only thing i found was that the drive shaft is about .0625 out of true at the frount and ford spec is .030 pinion bearing and trans bearings are tight any ideas would help i dont know if it could be the tranny it shifts fine and there is no vibration when you rev it in park to rule out tork converter and a new drive shaft is about 600 bucks the truck only has 80,000 miles on it

 

Tires are balanced at a specific speed; if you are typically driving 70+ you have two options.

1. have your tires balanced at a speed you don't drive at; maybe 60 MPH.
2. slow down.

 

I would take your driveshaft to a shop and have them check the balance.

 

We all know what tire imbalance feels like. Driveshaft-related problems have a very different feel because, at any given road speed, driveshaft RPM in a Ranger is roughly 4 times as high as wheel RPM due to the axle reduction ratio. It is not difficult to feel the difference between imbalance problems at the tire/wheel compared to something being driven by the much higher DS frequency.

If tire imbalance can be thought of as a "thump", then balance problems at DS frequency might be more of a "buzz". This comparison is weak but it's the best I think of right now.