If in doubt, fit new. easy to get as it's not a special part.
This assembly is the transmission oil pump. It is driven off the primary gear on the clutch assy. It sucks up filtered oil from the bottom of the tranny and feeds it to the inside of the gear shafts.
If you're feeling daring you can remove it and run splash lubrication like the RS. You might gain a tenth of a hp, but it won't be long before you're looking to buy new gear parts that have worn out
