To answer your question, the transmission is filled with a 60-wt non-detergent oil.
To address the theory that servicing the transmission to avoid problem later is ludicrous. It is not the oil which fails, but the internal gears and bearings.
(No one burns out that many transmissions without some sort of abuse factor figured in. )Besides, damage to the clutch & drive block is more likely that outright transmission failure. Regardless of the number of persons using the machine, if it is not overloaded, this kind of damage would take years to occur.