I have a 91 300e 4matic, and it's leaking hydraulic fluid from the system, its a fairly slow leak, but is now starting to leave marks on my drive.

When I've looked underneath, there is not an identifiable location for the leak, and not having cleaned the transfercase yet,i haven't pinpointed it. I'm wondering if you have any experience with respect to common places of gasket failure. My local Mercedes mechanic said that new gaskets probably won't solve the problem as they all leak.

What experience do you have with them?

Thanks in advance