I have a 1977 4 door nova and have been havind some problems. i just recently got it registered and have drove it to work a couple times. one day i got in my car and it wouldnt drive, almost all the tranny fluid was gone.when i put in more i also put in something to stop the leak, whitch at the time is what i thought it was. i put in a little more fluid in but i put a quart too much. about 15-30 sec. after i did this white smoke started to come out of the exuast. i took out the eccess and about a week later had my uncle replace the transmission vacuum modulator becuase that had stopped working, so i guess thats why i kept running out of tranny fluid cuase it was running thur engine. anyways he replaced it and now it wont shift gears. what on earth could be the problem now? mabe i had gotten the wrong vacuum. the one that the guy at advanced auto parts gave me was a tiny bit smaller than the original.