In a 1991 Dodge Dynasty with a 3.0 litre engine.Automatic Transmission, while driving the car up hill when the car needs to shift down sometimes all it will do is Rev up and if you let up off the throttle it seams to catch up and drive just for a while and then it will do it again while going up hill, sometimes it will even do it on level ground. Are there adjustments in the transmission that can be made or are they all Computer controlled?.