hi i would like to know what are the reasons that can lead to wear and tear on the main gear seal causing it to leak gear oil?the vehicle is an alto vxr 2006 model!whenever i park the car sumwhere and later drive off there are huge oil stains below the car!i got it checked the engine was clear there was no leakage from the tappet cover or engine/oil filter!the mechanic said that the main gear seal of the gearbox is leak!can any1 help me out as to why this happend?and what should be done now?can it be repaired in anyway or does it have to change?because the cost of replacing the seal is 250rs but the labour charges is 1800-2500rs if done from a workshop and road side mechanic will charge 800rs since the whole gearbox will have to be removed! plz help...