there are two in the area, one is at the gearbox side, and another one is at the engine side. iam suspecting the engine's side is fecked since u r losing oil. since the oil loss is at a high rate, iam suspecting the seal is knocked out of its place, or its badly damaged. when was the last time u changed dis seal sir? changing dat shud curb ur problem, but as a safety precaution, since the gearbox is going to be brought down anyway, please change the oil seal on the gearbox side as well if u havent changed it for a long time. if u r using a manual tranny, check the clutch, bearing and pressure plate, for dat peace of mind