[HO455]

Progress was made today! But first let me correct my post from yesterday. I did not correctly post the angle directions. The correct information is:
Transmission 3.5 degrees down
Front shaft 0 degrees
Rear shaft 2 degrees UP
Pinon angle 2 degrees DOWN
I jacked the rear of the transmission up and slid a 1/2" piece of plate under the mount, lowered the transmission back down and after double checking my ride height, I took a new round of readings.
Now the transmission angle is 2 degrees and the front shaft is 1 degree. Victory at that end! The second shaft was now just shy of 2 degrees. Now with a one degree difference between the transmission and the front shaft angles, and with the pinon and the transmission at the same angle I should be good as long as the other two u-joint angles aren't too extreme This arrangement puts the u-joint operating angles at:
Front 1*
Center 3*
Rear. 4*
A one degree shim under the axle would make things perfect. But I don't think that it will be necessary. So I drilled a couple of holes in the plate and bolted it in place.
As LockDoc says there's always one more monkey wrench! I needed to replace the old tranny mount bolts with longer ones and knowing that at some point GM switched to metric fasteners on the mounts I cleaned the old bolts to make sure I got the correct fasteners. This lead to the discovery that the PO had apparently cranked metric bolts into the standard thread mount. After bolting the mount down the new 3/8 NC bolts and one came up tight and one didn't. I guess a new mount is in order. I hope it won't change the geometry, but we will see. I had to remove the metal loop strap that goes around the emergency brake cable to get a good reading on the yolk and that bolt was stripped too. My poor Burban must have been owned by a neanderthal at some point.
I got the WMB back down on the ground and went for a drive. The harsh vibration is now gone.
Today's post accompanied by Doug MacLeod.

https://m.youtube.com/watch?v=h2R8OTXJsxw