Hough H50B Questions

I have a 1963 Hough H50B Gas Job, and I want to do a transmission service on it since it hasn't been done in the 15 years I have had it. Does anyone know a part # or filter that work for this transmission I could use? Doesn't matter what brand filter it is. I know its a paper cartridge style filter. Also how often should the planetary hubs be serviced, drain and refilled? I Know I haven't serviced them in the 15 years Ive had it. And who knows if it was done before I got it. I estimate this...

Hough H50B Questions

Hough H50B Questions