Mine developed a leak in about 5K miles; never seemed to lose much. But it would make a little "deposit" on my garage floor from time to time, and ANY drip from my vehicles is flat unacceptable. Mag-Hytec, without having to RTV, but with just a little de-burring, and Amsoil and it's been pristine! I'm really looking forward to Mag-Hytec's front diff cover...