Vibration right off idle

I have never seen the output shaft on a car or truck point upward (toward the sky).

@plumkrazee70 has it correct. 2 degrees down from parallel may be too much though if the front half of the springs are super stiff. I'd try it with the pinion at parallel and at 1 Deg down from parallel just to see how it runs.

Could also be that the vibration is from the engine and when the OD kicks in, the revs drop and the vibration goes away. Could be in the trans too, but I wouldn't know where to start looking for that.