Fluid Level

Check that the fluid level in the reservoir tank is within the specified range (MAX - MIN lines).
Visually check for any clutch fluid leakage around the reservoir tank.
Check the clutch system for any leakage if the fluid level is extremely low (lower than MIN).

Fig 1: Identifying Brake Fluid Maximum And Minimum Level On Reservoir Tank

Courtesy of NISSAN NORTH AMERICA, INC.