The axle does need to be removed to replace the axle bearing. The axle bearings are not pressed onto the axle shaft, they are pressed into the axle tube. It will take a puller to get the bearing out. I used a slide hammer style. You would need to inspect the surface of the axle where the bearing rides for wear. I'm not sure how much is acceptable if any, but I had no wear on mine, just shiney. The axle is held into the rear end with a "c" shaped clip, of course. When you remove the diff cover, examine the fluid for metal debris and also look in the bottom of the diff housing. A little bit of metal flakes is normal but alot would indicate something failing. You can look for obvoius problems but otherwise it would take someone who knows what to look for. Next you have to remove the carrier pin which is held in place by a small, long retainer bolt that runs thru the pin. Once the retainer bolt is removed, the pin may slide out or you may have to coax it alittle. You may also need to rotate the diff to get it to slide into your hand rather than into the diff housing. The carrier pin is big, heavy, and slippery so hang on. (Quit it, you perverts) I would not recomend removing the spider gears, they can be a p-i-t-a to put back in. They can fall out with the carrier pin removed though so don't rotate the carrier. No you can push the axle in toward the car which will expose the c clip on the end of the axle right there in the space where the pin was. It slides off and now the axle is free to be pulled out of the rear end. You'll be able to see how, if the c clip fails, it's bye bye axle and wheel 
With the axle out, use a puller to remove the bearing from the axle tube. I borrowed mine from Autozone. To install the new bearing you will need a hammer and a tool to knock it in with. Don't beat directly on the bearing, you will damage it. Find something like a big socket that's the same diameter as the bearing or close to it so that it is pushing on the outer diameter of the bearing. Be sure that it is fully seated on the lip inside the axle tube and not cocked. Geese, I didn't mention the axle seal which must be remove before the bearing. Just rip it out however you can without scaring the axle tube. Don't try to save it, it will never happen. After the bearing is installed, tap on the new seal (I used a hockey puck) and put some lube on the seal where it rides on the axle, then slide the axle back in and put everything back together. This may sound complicated but if you watched someone else do you would see how simple it is. Be careful not to damage the lip of the seal when sliding the axle back in because your rear brakes don't work well when lubricated. 
Whew! This was long!
With the axle out, use a puller to remove the bearing from the axle tube. I borrowed mine from Autozone. To install the new bearing you will need a hammer and a tool to knock it in with. Don't beat directly on the bearing, you will damage it. Find something like a big socket that's the same diameter as the bearing or close to it so that it is pushing on the outer diameter of the bearing. Be sure that it is fully seated on the lip inside the axle tube and not cocked. Geese, I didn't mention the axle seal which must be remove before the bearing. Just rip it out however you can without scaring the axle tube. Don't try to save it, it will never happen. After the bearing is installed, tap on the new seal (I used a hockey puck) and put some lube on the seal where it rides on the axle, then slide the axle back in and put everything back together. This may sound complicated but if you watched someone else do you would see how simple it is. Be careful not to damage the lip of the seal when sliding the axle back in because your rear brakes don't work well when lubricated. Whew! This was long!
in reality i put in about 2.75 quarts...how much should i fill the rear up? i mean i heard cap is 2 quarts or something...did i put too much fluid in or is that even possible?
