<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Jim,<div class=""><br class=""></div><div class="">How are your motor and trans mounts? If they allow the engine/gearbox combo to shift out of line when under high torque, the u-joints could move out of proper alignment, but then when power is reduced, things would shift back into position. If you put the car on jackstands and run it to this rpm in top gear (might not be a bad idea to remove the drive wheels and tires if you’re sure they’re balanced) there won’t be much load on the engine, so if the vibration is due to deformation of the mounts, the vibration should not appear.</div><div class=""><div class=""><div class=""><br class=""><div class=""><div class="">Duncan</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 15, 2015, at 10:55 AM, <a href="mailto:toodamnfunky@comcast.net" class="">toodamnfunky@comcast.net</a> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class=""><div style="font-family: Arial; font-size: 12pt;" class=""><div class="">FoT,<br aria-label="Compose body" class=""></div>
<div class="">I have a driveline vibration that doesn't start up until I get to about 95- 100 MPH. I figured I would start with the driveshaft</div>
<div class="">before looking into the diff or OD/trans. I have an IRS car with Richard Good CV axles and hubs so it's very un likely its that but</div>
<div class="">I will inspect them. I'm wondering if anybody has any advice on high speed vibration diagnosis or detection.</div>
<div class="">What I'm wondering is even if it is the driveshaft how would I know with it sitting on my bench. </div>
<div class="">Any help would, as always be greatly appreciated.</div>
<div class="">Jim g</div></div></div>_______________________________________________<br class=""><a href="mailto:fot@autox.team.net" class="">fot@autox.team.net</a><br class=""><br class="">http://www.fot-racing.com<br class=""><br class="">Donate: http://www.team.net/donate.html<br class="">Archive: http://www.team.net/archive<br class="">Forums: http://www.team.net/forums<br class="">Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/duncan.charlton54@gmail.com<br class=""><br class=""><br class=""></div></blockquote></div><br class=""></div></div></div></div></div></body></html>