[maxwoof]

This is correct. There are oil seals close to the differential that keep the oil in the pumpkin from leaking out to the knuckles. I have been running the truck with the knuckles dry for a few months now with no leaks. My feeling is that with the wheel bearings packed with grease, and the knuckle bearings too, and using grease-able u-joints, I am basically running the same set up as a later open knuckle, just in a closed knuckle housing. The only downside is that to grease the U-joints, you have to pull the axles. However, given the miles I put on the truck, (even less using 4 wheel drive) If I grease every 10K miles, that would probably be every 6-8 years.