About a month ago I was driving to work in D, and all of a sudden a loud "VROOM" sound came from the engine, and it downshifted to about 33MPH. My 90 maro has been stuck like ever since, and I can't figure out why. It will not shift past 1st gear in D or OD, but will go into second if I put it into 2. I have an auto transmission. Any suggestions?