Where to put hydraulic fluid in astra gearbox?

To add hydraulic fluid to an Astra gearbox, locate the transmission dipstick or filler plug, usually found on the top or side of the gearbox. If there’s a dipstick, remove it, wipe it clean, reinsert, and check the level. If there's a filler plug, remove it and use a funnel to add the appropriate type of hydraulic fluid until it reaches the correct level. Always refer to the vehicle’s manual for specific instructions and fluid specifications.