The axle doesn't have oil only grease and possibly transmission fluid leaking but most likely not. Sounds more like a leaking front passenger shock that is bad or a leak in the brake line. Those two would most likely be the culprit. If you check your brake master cylinder and it is low then most likely there is a small leak in the brake line and you need to get that fix right away or it can the whole line could burst and you won't be able to stop your car. If it is a shock that is leaking it isn't a major safety issue as the brake line. Other than that it could be your oil filter has spun loose and is leaking.