I found I have a parts and basic maintenance manuals for that. The strainer is in the fitting with a hose clamped on it just behind the left wheel. The drain plug is just under that. If all is good with the strainer and there is no pressure coming out of the hose under the trans filter then there must be a problem with the pump or relief valve. Inside the housing that bolts to the back of the motor are gears that drive the 2 pumps. The torque convertor is a special type that the nose fits into a gear to do all that. There are sealing rings, like the ones on transmissions shafts (steel), to seal where the torque convertor fits into the main drive gear. The trans pump is keyed on to one of the shafts in there with a woodruff key. There is also a check valve with a spring and ball next to the temp sensor switch. My take is if the screen is ok, and the pressure relief is ok (there is a ball and spring and spool in there), and the check valve is ok, then the pump must have a problem. That would require taking the cover off the housing that is bolted to the motor with the torque convertor in it. Maybe try taking the filter off and starting it. If there is no sign of oil, or sound of a pump trying to do something, it's time to go in. I can sent some pics later today if you want.