So I finally got my stang back on the road after a bunch of work. Long story short, I am experiencing some vibrations that start at 45mph and continues on through 65mph and beyond. I notice the vibrations more when I am OFF the gas coasting at the speeds mentioned above. Once I give it a little gas, the vibrations die down just a little but they are still there. It doesn't matter what gear I am in, the vibrations seem to be speed related.
I've checked and ruled out these items below:
1. Mounted and balanced my tires twice by two different shops. They told me there was one tire that was out of balance and my rims aren't bent in any way that would cause vibrations.
2. Driveshaft was also balanced twice by two different shops. I had to cut about a half inch off my driveshaft so that's why I had to balance it again.
3. U joints are brand new and don't appear to have any play.
4. Rear end was rebuilt with new bearings.
5. Checked to see if exhaust system was possibly rubbing on any engine parts. Steering box and rear axle clear any parts of the exhausts system.
6. I inflated my tires to about 38psi to rule out the tires (just in case). That didn't make any difference.
7. I don't think its engine vibrations as pushing the clutch in doesn't change the vibrations at the speeds mentioned above.
8. Checked my brakes to see if they might be rubbing. Brakes are all good.
9. Transmission mounts are brand new and rubber is in great condition.
10. Tried rotating the U joints on the pinion yoke
I think I have an idea of what the issue might be, but I want to see if others come to the same conclusion.