96 Tahoe Rear Differential Problems

When we pulled out the half axle to replace a grease seal we noticed some play in the gears, and we could move the ring gear about a half inch back and forth. We pulled out the carrier and found out the part that the side bearing slides on was broken off. I am now trying to find a new carrier (or axle) and will install it (attempt to). Does anyone know if this is a common problem or what may have cause the break? As far as I can tell, everything else looks good. Also any advice before we try to install a new part?

(10 Bolt w/ 3.73 Gear Ratio, w/ Limited Slip)