Kubota RT120Q Operator's Manual page 179

Service - 178
Check Differential Oil Level
Check oil level at fill (shown) every 250 hours. Add
MPL as needed.
Check Planetary Wheel End Oil
Remove track to check oil level in planetary wheel
ends every 250 hours. Add MPL as needed.
t37om028w.eps
Level
t37om029w.eps
RT120Q Operator's Manual
250 Hour