You didn't lose the grease. The bearing just decided to fail. You either had the windows down on a hot day or really had the tunes cranked up on the old stereo to not hear that puppy yelling. At any rate it sounds to me like you drove on it to the point where the race spun on the spindle or the spindle was heated past safe temperature. In either case I would recommend a used one from the bone yard. You may need to invest in a tie rod puller. I would also suggest repacking the bearings on the other side.
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