Just because it idles smooth, you maybe assuming something here.
This is running up to 4500 rpm in first and second. Smooth.
It appears as of 40 mph (in both third and fourth gear) and gets more annoying at 50-60. It’s a buzzing kind of vibration. It seems to still be there in coast and neutral.
Sooooo, I measured the angles again.
All angles are going down from the front of the car to the rear.
Trans: 2.0
Shaft: 1.1
Diff: 0.4
This is as accurate as I could measure, measuring repeatedly and carefully as I could.
According to the Tremec app, this is fine.
Then using a magnetic laser
Spot on.
The driveshaft, that I had to drop to check the angles, the U-joints feel just fine and no needles missing.
I will check the half-shafts... tomorrow. Those, as far as I know, are not balanced on C3 corvettes.
ADD - however, I do feel the vibration is too fast to be the half-shafts.
That leaves the transmission and the differential.
That being said I came across something curious
. The driveshaft to yoke bolts were not as tight as I left them. I won’t say they were loose, but they definitely were coming loose. And that’s the second time that happened. To me, this is a hint that the vibration is possibly coming from within the Muncie.
If it was the diff, I’d suspect I could rattle the pinion yoke around a bit in the bushing and I can’t.
Tomorrow I’ll flip the driveshaft 180 degrees in relation to the pinion.
Then I’m out of ideas.