Hi, today something wrong happened with my gearbox, car is only rear wheel drive, front wheel dont have power and when i set car to 1 gear i can move it, like it is without gear in. When its happened i accelerated little bit harder then strange sound and thats all, now when moving dont have strange sounds, but car is only with rear wheel drive. How seriously it can be? Can i drive like that or better dont do it? Thanks.