ccog: Looks to be a pretty old Chelsea or possible a Spicer brand PTO. They are now combined as Chelsea under the Parker Hydraulics banner. The seals are fairly common. This model was designed as a lever shift unit even tho' someone has adapted a cable to it. The floor mounted shift lever was the advantage it used to make shifting it easy.
orchidskip: Yours is a much later Chelsea double gear unit. That "round thing" is a freeze plug I think and very simple to repair. This model was designed as a cable shift PTO and used the short lever to gain mechanical advantage. It is a much heavier duty model than the single gear types and is usually found on heavier transmissions with a lot of torque on the driven gear.
Incidently, FWIW, the early Muncie brand PTO's up thru the eighties were actually Chelsea's and were assembled, branded and sold under the Muncie tradename. They are now all aluminum and are of Muncie's own manufacture and owned by an Italian company. At least they aren't Chinese or made in Mexico. I think?
