My m46 has a noticeable little seeping at the rear output seal. There is no leak but it looks a little shiny there so I know.
This explains why I missed fluid when not checking for so many years. Use the proper fluid only! I tilted the car and slightly* overfilled to compensate temporarily.
(I will tackle the output seal project hopefully in Summer.)
When I replaced fluid I also removed the square OD cover for a perfect draining then cleaned the filter in there, also removed the little pistons and parts for inspection and cleaning. Found grey metal paste in filter, it was worth checking!
The pan gasket is still available to order, I already bought one. Very careful when tightening drain plugs and the four small bolts holding overdrive lid. It is just an aluminum cover, not the crank nut
