I was planning on adding some of the Sea Foam Trans Fluid into my auto tranny tonight to see if it would help my rough shifting, and when I checked the fluid level it was WAY above the two notches that it should be between.....and from what my Haynes manual says, thats a bad thing.

I haven't had my tranny fluid replaced since almost a year ago, so its been overfull since then.
Would this be to blame for my rough shifting? (i.e. when I manually put it into reverse the truck violently "lurches" and when I manually shift into drive I get this "ping!" sound.)

 

First, did you check with the engine running, in park, and at operating temp?
If not, this could give you a false reading. It is possible that too much fluid could make the trans act up, so if it is over full, drain out enough to bring it to the correct level and see if the problems go away. It can't hurt to try this first.

 

The first time I checked it, it was at operating temperature but my engine was off. So I went out and drove it around some more and checked it with the engine running and it wasn't as overfilled, but its still a good 1/2 inch above the top notch.
I'll try draining it a little bit and see if that helps.
Thanks for the reply!