Hello, my 1989 Buick Reatta stopped shifting today. I had been out all day and it has shifted fine. I went to leave my friend's house, and noticed that the car wouldn't shift out of 1st gear. I tried turning it off, waiting some time, and turning it back on again but it still has the issue. I tried using the manual gear selector and it still wouldn't shift. Car goes into park and reverse and neutral just fine, but when in either drive mode, it just stays in 1st. The car has a vacuum leak that I am aware of, but it has driven fine before then. Please, help me out here, I'm only 17 years old with little mechanical knowledge but I will do my best to understand. Thanks all.