Gear retraction is achieved using fluid pumped into hydraulic cylinders from the reservoir, which pushes the landing gear up into the wheel well. The fluid is trapped when landing gear lever if selected OFF. The fluid is then released for returning to reservoir when wheels are extended.
Skyjob,
Are you saying you always gravity drop your landing gear on your aircraft? How does your landing gear lock down?
Just asking the question out of curiosity. All the hydraulic retractable gear aircraft I've flown move landing gear under hydraulic pressure in both directions.