I just did mine about 3 weeks ago with no leaks. One other reason that they will leak is because the pinion nut needs 470 ft/lbs torque to get things to fit together. I have the special socket that it takes to take the nut off the Dana 80. If you need to replace it again, you will need a torque multiplier to get the job done. Let me know if you do this yourself, I will send you the socket. . You will have to get the torque multiplier.