Kubota RT120Q Operator's Manual page 173

Service - 172
Trencher
Check Trencher Gearbox Oil Level
Check oil at sight tube every 50 hours. Keep oil
level at horizontal line on housing. If necessary,
add MPL at fill plug.
Plow
Change Plow Vibrator Oil
Hot parts may cause burns. Do not touch until
cool or wear gloves.
Change plow vibrator oil after first 50 hours of
operation. Drain oil at drain plug (2). Replace plug
and move plow vibrator to horizontal position. Add
MPL at fill (1) until oil is halfway up sight glass (2).
Refill capacity is 4 qt (3.8 L).
RT120Q Operator's Manual
50 Hour