It should be the a4ld tranny, first and second shift are controlled by a vacuum modulator on the passenger side of the tranny, and 3-4 are computer controlled. I would almost best that the modulator is bad, look for the vacuum line come from the modulator to the intake and check for any fluid in the hose. Also there is two bands in the tranny, they require being torqued to a certain in/lbs and backed off I believe two turns.