Kubota finish mower gearbox

[bandmiller2]

I  scooped a deal on a Kubota B7100 fwd diesel with a 48" three point finish mower.Question on the mower gearbox the label says "prelubericated check and use nonfiberous wheel bearing grease. That seems strange every gearbox I've ever had used heavy gear oil,grease channels and you can't drain it.The seals seem tight I may mix in a little 140 with the grease in it now. What are your thoughts. I don't have the operators manual. Frank C.