Massey 35 oil leak

I'm new here, this my first post too. I need a little help solving an oil leak coming out of the bell housing through the drain hole. It's pretty bad it will leak 2 quarts in about 4 hours of bush hogging. I have already replaced the rear main seal it's the rope one. I put a new gasket on the rear main seal retainer. It's been leaking but not this bad. It's an old tractor I believe it's a 64 or 65 model. I've been fixing it up and have replaced a ton of parts. The transmission was leaking hyd oil or a better description it was being pumped out. 2 new seals stopped this problem and I thought I had solved the oil leak at the same time. So it looks like I'll be breaking it in half yet again. Is there anything else I have to do to stop the oil leak?

Thanks Bob

Massey 35 oil leak