94 Buick park ave Trans Problem

hi my name is tom i just purchased a 94 buick park ave 3.8 from a local auction and it has what i think is a minor or major trans problom not sure

the symptom is the 1 2 3 4 od and lock up all work but it shifts too fast an does not go into passing gear at all also when it sits for a couple of hours it does not go in gear till it warms up but once warm goes an shifts firm but to fast an no passing gear unless you do it manualy with gear shift what could cause these symptoms an do i have to pull or replace the trans or can this be resolved buy way of sensor or trans control mod or what ? please help
a.s a.p thanks tom denkler

You obviously have an input shaft/drum seal leak, which will cause low line pressure & delayed engagement when below 50 deg. When you first start the car, let it idle as long as possible then shift to reverse or first gear and let it engage in one of those gears. Once the initial engagement takes place, you can then shift to D and it should work fine (until the next cold start). Some folks drain the fluid & replace the filter along with a quart of Lucus transmission treatment to help remedy this problem for the short term. Of course, the only long-term solution, is a complete trans rebuild. Good Luck!