70+ mph rumble and vibration

2001 with NP231 and 8.25. 2" OME lift and a homebrew H&T SYE. I have a very pronounced rumble/vibration at 70+ mph which goes away above 80 mph. I have set my pinion properly I believe (using a angle gauge): http://brentroad.com/photo_photo.aspx?user=21295&photo=531431

I've had the rumble noise prior to the lift and SYE (6 years ago). New tires (2 sets), several alignments, new tire balance, a new Tom Woods driveshaft, a new rear pinion yoke and the noise is still there...no worse and no better.

Here's the catch: if I'm cruising at 75 mph and let off the gas to coast, the noise greatly diminishes. Thoughts and ideas are greatly appreciated.

Check to make sure your yoke nuts are tight.

All nuts down there are tight. Also, I wanted to add: removing the front driveshaft makes no difference to the noise, so I've ruled that out.

if youve had the vibe for 6 years and nothing has failed yet, i'd just let it go... lol

XJLI said:

if youve had the vibe for 6 years and nothing has failed yet, i'd just let it go... lol

Click to expand...

Kinda what I was thinking.

I had a similar vibe issue that was basically my CV on the rear driveshaft being right at the end of it's range of motion, making some contact with ears. You would think this would be constantly noticeable, but it was really only at high speed hot spots. But if this preceded the lift and your current DS, either of those things would almost have to at least change the behavior. So I dunno. Any major issue, like bad gear setup, would have manifested in a failure by now, one would think.

If your front DS is super awesome and you have an SYE, you could take the rear DS out and see what happens at high speed...? You have already covered everything I thought it might be. :thumbup: