Honda HP500H Manuel De L'utilisateur page 20

Hydrostatic transmission (HST) fluid
Check the transmission fluid level when the transmission is cold and
with the power carrier parked on level ground.
Make sure the fluid level is between the upper and lower marks on the
reservoir. If the level has dropped close to or below the lower mark, add
the recommended transmission fluid until it reaches the upper mark as
follows.
Recommended fluid
Use 4-stroke motor oil that meets or exceeds the requirements for API
service classification SE or later (or equivalent). Always check the API
service label on the oil container to be sure it includes the letters SE or
later (or equivalent).
1.Unscrew the reservoir cap and remove the seal. Be careful to prevent
dirt and water from entering the reservoir.
2.Add recommended fluid to bring the fluid level to the UPPER level
mark. Do not overfill.
3.Reinstall the seal, and tighten the cap securely.
CAUTION:
Operating the power carrier with low transmission fluid level will cause
serious transmission damage. Stop the power carrier immediately and
have it checked by your Honda power carrier dealer.
TRANSMISSION
FLUID RESERVOIR
UPPER LEVEL
LOWER LEVEL
RESERVOIR CAP
SEAL
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