Auto Gear Doesn't Engage

[gilera_200]

Hi guys,Well yesterday i was driving around and suddenly my car just rev like it's in the N position although it's in D position. Pulled over and tried each and every gear positions yet failed to engage. So tow trucked the car to my mech. Since it's Sunday my car hasn't been diagnose for its faulty. Would appreciate if the sifus in here can advise on what I might be facing. The car is a M40 Auto and there was no leak what so ever. Thanks in advance.