[tankman67]

I thought my transmission was shifting hard until I realized the upper differential mount was shot. Replaced that and the transmission was smooth as butter. ...just something to check if you haven't already.

 

[tankman67]

Wouldn't that happen in all shifts, not just 1 - 2?
And on downshifts too?

Actually ya, I did notice it most on 2-1 downshifts when there was less torque on it, but could hear it on 1-2 shifts as well. I just reread the thread and see you do NOT experience the symptom on downshifts, so this might not be the issue but probably still worth checking them since the bushings are prone to failure.