Yeah I mean 1/2 degree. I'm right now between 1/2 and 1 degree downward. (closer to 1/2) Which from everything I've read is perfect, and confirmed by a couple of sources. Ideally this angle is 0 degrees, but the downward angle is to account for axle wrap on acceleration.

I had an 8 degree shim in before so pinion was about 2.5 to 3 degrees downward. The vibe was still there, on acceleration. My understanding is if the pinion is pointed too far down any vibes related to pinion angle will be on deceleration.

Anyway, putting the 10 degree in there helped a little, I think. The difference was subtle. But I wouldn't want to run anything steeper than that.