Visually inspect the gearbox exterior for signs of overheating.
Inspect gearbox for exterior damages.
Inspect mounting bolts to ensure tightness.
Look for oil leaks at the shaft seals
Inspect oil for discoloration and level. (add oil as needed)
Examine the inspection port cover and determine whether all bolts are tight, and the cover is properly sealed or if there is oil leakage.
Clean the Gearbox
Ensure Correct Breather Types & Style. Clean as needed.
Perform Regular Lubrication. (drain oil every 6 months or as needed).
Temp check. (anything over 150 degrees report to supervisor)
Inspect shaft for play and wear.
Source: MaintainX (Community Member)