I saw your post about the engine pan gasket and the Yamabond. I paid a self proclaimed 928 expert to do a bit of service this spring and have spent the summer fixing his messes rather than driving the thing.
Anyway, the one thing I can't seem to fix is the newly leaky auto-trans pan gasket. It has leaked badly since he did the transmission "service". I have pulled the pan twice so far and tried to figure out what is amiss. It seems as though those little stand-offs that are stamped into the pan at the bolt holes are responsible for determining the gasket crush when the bolts are properly torqued. I suspect gross over-tightening by the "expert" because the bolts were tough to break loose and the spec'd 70 inch-pounds isn't all that much. I tried 50 and 60 in-lb and it leaked worse than at 70 in-lb. I tried 75 and 80 and 85 in-lb increments, and each greater value made it leak worse than the previous one, too. I placed the pan, face down on a piece of glass, and there is no apparent twist to the pan, but I can't determine if that "gasket crush" value has been altered.
Dare I try some Yamabond there?
Thanks for your kind attention to this query.
The gasket can also leak due to a weak spot in the design. The original tranny is from Mercedes and they made an improved seal to cover a weak spot at one curves where it goes around the bolts in the mid range of the pan. It is best to order Mercedes number: A1262711180 (not A1262711080)