Some Mystery ,Ill give it a guess ,reason a flow wont move in some cases , air above and the release of liquid below may cause a suction.Your trannie breather clogged with the trannie dipstick tight on tube somehow.Always do the converter, you can get a 27mm socket on the frt crank bolt and move the engine clockwise with one hand and reach at the tc with the other waiting for the drain nut on the tc, I beleive a 5 or 6 hex tool.Thats the liquid thats going to bring you to a complete trannie service.A new filter can then do its job with fresh fluid.