Try checking for a vacuum sound around the spot where all the vacuum lines are hooked into the intake manifold-that hook up has an O ring that can disintergrate and cause a leak. You can take it off with a 10mm socket and pull the part out and check faily easy. The dip stick for the tranny is located way down on the right of the engine. The tranny is supposed to be filled for life from Volvo-if you belive this and stick to it it is a wonder your car has lasted this long-has the tranny fluid ever been changed in the car- if not check under the 960 faqs for the tranny flush and learn how to change the fluid out and do so.
Poolman