thanksYou try to load your car by 3 fat man sit on rear seat then start engine and press pedal to 2000 rpm for 10 second if it still too low try to check as list
1. drop oil- see ground under your car
2. leak oil - see at each rear wheel and see from under your car at rear wheel it must be clean
ps. check your oil level may not indicate leak oil because they have regulating valve to stop leak from over pressure in each hydraulic line.