1994 auto transmission problem

94 z28, transmission with 230000 miles has delayed shift into last gear but still shifts if i let up on it or punch it a little. replaced 1-2 and 2-3 solenoids; no change. replaced pressure switch; no change. replaced throttle position sensor and vehicle speed sensor; no change. any ideas? i also checked the pressure solenoid and its ok. i think if any components fail in there i will get a code but so far no codes.

transmission runs ok when cold. problem appears usually after it is warmed up and hot.

there are no metal filings in fluid so hardware is ok i think.

help!

Make sure the oil relief hole along the right pan rail is not obstructed. This hole relieves oil from the 2nd servo so that the 4th servo can apply the band for OD. Incorrect pan gasket alignment and overuse of gasket sealant can cause problem sin this area.

wow! that is really amazing--thank you! I NEVER would have guessed that--heck, i didn't even notice that hole. I will check it out and get back to you during the next week or so. I bet that's it because when i change the fluid and filter i always wipe down the surface and i bet i wiped dirt right into that little hole.