Rear Axle / Differencial vent fluid leaking. I have taken my 2012 Mustang GT into the dealership four times during the past two months and they are unable to correct a fluid leak in the rear axle. The dealership has now indicated that they are unable to repair and are seeking the assistance of the Ford Hotline Tech / Engineering dept. Temporarily, they have lowered the fluid level 1/2 inch. Is the vehicle safe to drive and also avoid any further damage?