My car is not shifting properly, especially into 4th gear. on 1995 Geo Prizm

If I take it to 4500 rpm's then let my foot off the gas and give it gas again it shifts. my normal shift rpm's is around 3500. I have changed the fluid and it looked good. A small screw fell out of the pan.

Asked by for the 1995 Geo Prizm
seek diagnostic at local aamco trans