Depending on which seal(s) is leaking, specialized tools and expertise are required. IMO, your best course is to get the unit to a good shop for a proper diagnosis aka pressure test. Since you have already drained water from the unit, I would refill it with the proper lube to prevent corrosion. I would consider an impeller change while you're in it. Depending on the what parts are required plus labor, you're probably looking at a couple hundred $$'s at a minimum and very possibly more. Best of luck whichever you decide.