Sounds to me like you have a lack of pressure. This can be caused by wear on bushings and seals. I have never done this on an AW4, but you can upgrade the spring in the reserve servo in the valve body. That is one of the items changed out in shift kits to give a better pressure. If you do this, you will have to drop the pan, change the filter while you are at it and change it out. It is a large (reletavely) pointing down on the valve body and replace the spring with a heavier one and O rings