I have the leak on the back and side of the tranny, PO has warpped the tranny pan. A new pan-gaskit and pan fix the main leak. I had to replace 2 Orings on the back to fix the minnor leak. It did seems like that it was leaking from the front. Make sure about the source, I cleaned the outside with parts cleaner, dried it, Started the car and crawled under the car occassionally to find the source of leak. Took few tries but finally was able to resolve the issue. My 420sel has 156K miles and no pump issue neither I heard this before.
Now if I can figure out how to reseal the steering boxk, I will not have any leaks at all.
I hope it helps, keep us posted.
Thanks

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87 420 SEL
Looking for a nice mid 80's MB diesel.
87 BMW 528e (Sold)
99 TOYOTA 4Runner
1989 Honda Accord (Sold)
1988 Honda Accord (Total)