Use Timken Set 20 and never look back
http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40
The above is a Tapered cone bearing set capable of carrying more load and side thrust. I believe it was found in truck applications in OEM. It adapts to our usage because many of us like to carve corners, race and use copius amounts of HORSEPOWER.
The other application is a Roller Ball and is a little less expensive and is consequently used more often in passenger car application.
BKLIST: you have either a bad axle shaft seal or the outer bearing retainer is allowing lubricant to seep between it and the housing end that it bolts to, either one is not a real big fix but will neccesitate pulling the axle. You may also want to check the axle housing vent which is on the tube itself, the lubricant is forced into the axle tube in turns and could be forced out the vent(?).