Dana 30 axle seals

[Whips 17]

Hi does anyone else have problems with were front axle seals leaking? I have replaced twice now and still leaks after I go 4x4ing. And also the front pinion on the Dana 300 transfer case?
Thks

80 CJ-7 350 on propane. TH400. Dana300. Detroit truetrac front and back. 33"Copper STT