i finally got the nuts of the axle and the axle off to put new bearings in.When i removed the diff from the driveshaft tube(swing arm)oil came out. Is this normal? If so how do I fill it up? It may indicate a leak.Any help would be appreciated.Thanks

 

No, but as you had oil on the outside, which had to come from the inside, this is hardly surprising. Gear oil means a leaky pinion seal on the diff, engine oil means that seal on the back of the transfer box is leaking.

Too long since I did one but I didn't think you needed to take the diff off to change a wheel bearing on those old Big Bear/Moto4s.