Well, I followed your tips and drilled a drain hole, after inspecting the insides of the unit I replaced in the customer's Flex. After you remove the heat shield over the exhaust pipe, there is a flat area at the bottom of the unit that is accessible to drill and is between the gearset, so will not hit any internal components when drilling. I had a 1/8 NPT tap, so carefully drilled a hole when the fluid was warm, then tapped hole, allowing black fluid to drain and flush out chips. Then used a funnel with a length of hose over the top of the engine, wire-tied away from the catalytic converter and into the PTU. I added the appropriate amount of Mercon V and drove slowly and carefully around the dealership and area for several minutes to circulate the fluid. I drained that and repeated twice more, until the fluid started to look more reddish than black, then drained it again and added 75W140 and repeated the drive cycle, then drained and filled a second time with the gear oil. No more smell. Thanks again for your ideas.
