What's the deal with it, how many RPM's, machine, techniques etc... I'm not 100% confident in the balance job my rear shaft has. I don't know how he balanced it if the Grease fitting wasn't even on it... Figured out that vibe I get from 65+ is 99& sure the Rear Dshaft. I've had the tires shaved, removed the wheel spacers, checked for runout, everything passes with flying colors. IIRC I called a few local jobs a while back to have it done and they only balanced it to 3K/4K rpm's.. that's not a whole lot. Figure 4th gear is 1:1 ratio. 5th gear is overdrive. so at 70mph in 5th i'm doing 3K. so that shaft is going faster than 3K rpm. Hence why i have a slight vibe. Does anyone do HIgh speed shaft balancing?