rearend fluid level question

something doesn't seem right here. I just replaced the axle bearings on the Duster. 8.75 rear. Had the car up on jackstands front and rear, level as I was under it checking it all out also. After I tightened the axles down, I pulled the plug on the side of the rearend and topped the fluid off till it started to run out of the plug. Put the plug back in and ran the car in drive a little while. went back under and pulled the plug again to make sure it was full. fluid ran out so I put plug back in and tightened it down. pulled the car out in the driveway. I knew I had the wrong brake drum on the right side but I needed to get the car out of the garage so I could bring the new compressor in and get it hooked up. I jacked the rear of the car back up just enough to clear the ground and get the tire off so I could take the brake drum with me to make sure I got the right one this time. I decided to pull one of the axles also and take it because I had an issue with the center hole diameter of the drum. Now the back of the car is back on jackstands just high enough to clear the ground with the tires, level and when I pulled the right axle back out, there was no fluid coming out of the axle housing. unless the rearend throws fluid into the axle tube when running and then drains out when stopped, something don't seem right to me. I think there should be some fluid in the tubes at all times. could someone tell me whats up here. do I need to jack up the front of the car and fill this so more fluid gets in the rearend or what.