Can having too much fluid cause the transmission to NOT shift after second gear? All I have right now is first and second. I think I added a little too much fluid. Just wondering if this is the case. Also what is the vacuum line coming off the transmission supposed to be attached too? Right now it has a screw in the vacuum line.

Too much fluid won't affect the shifting but if it's too overfull, it will puke out the vent tube.

What transmission? A 700R4 doesn't have a vaccum line. If it's been converted to a TH350, the modulator valve vaccum line needs to go to manifold vaccum for the transmission to upshift.

that line on the top of the trans is a vent tube

Well its a 700R4. Its not a turbo 350 due to the shape of the pan. Anyways when I bought the car this vacuum line was hooked into another crazy line that was plugged. It didnt make sense when I bought it. So if its the overflow line Im not sure why it was run up in the engine bay and plugged. A few days ago it shifted but it took a while too. So I added more fluid and it helped. I thought it might have needed more and now after adding the little bit it doesnt shift past 2nd gear. So I drained some out through the hardline going into the transmission and it didnt make a difference. I'm stumped now. Thanks for the replys so far. Eric