I had an old beater tiller that leaked the same way. The leak wasn't too bad, so I just refilled it before using.
I actually would give a few pumps with the grease gun in the fill plug first. I figured the grease would get churned up with the oil and thicken it some.
If your leak isn't too bad, maybe you could live with it?

So do you know if it should be filled with heavy weight oil or grease? This is the first piece of equipment I've not been able to find info by searching the internet. I try to work on my tools/equipment myself and I can almost feel my Daddy looking down and smiling...ok, laughing when I get myself into something like this!

Most likely, it was "gear" oil (90 to 140), but sometimes you do what you have to do.

It may be, that you could find some "standard" size oil seal at a "real" auto parts store, but you don't really know until you take it apart. Then, it's too late, if you can't find the right part!

Another option would be to check locally and see if you have a distributor for "Farm Oyl" products. A couple of the bearing supply places here carry their stuff, and I believe Tractor Supply does also.

Farm Oyl has a gear lube they call "Fluid Gear Grease". It comes in a quart squeeze-type bottle, and the grease is *thicker* coming out of the container than a regular gear lubricant, but *thinner* than a grease gun cartridge-style grease is.

Our bearing supply here sells a lot of it to farmers that would otherwise be spending all of their time tearing down gearboxes on equipment like augers and bush-hog mowers, because it doesn't seep past leaky seals as much.

Here's a link to Farm Oyl's site:

Here is a link that might be useful: Farm Oyl lubricants