OK so I am sure this is obvious for many however I have been searching for the answer and can't find anything definitive.

I am rebuilding the suspension on my 68 Series 2 and when I pulled the front axle out the housing there is a fair amount of what appears to be grease that has mixed with oil and perhaps some water. Also when I drained the front differential it had a similar fluid however more like a runny oil . I believe the seals failed at some point allowing the cross contamination? I understand how to rebuild and grease the hubs and to refill the differential with gear oil my questions is - does the axle also need to be filled with grease or will the oil from the diff find its way in? I plan to remove what is currently in the axle housing as it appears contaminated.