Support bearing.
The carrier is in your rear end, and the ring gear attaches to it. It has 2 bearings, and the pinion shaft has a bearing as well. The torque on that nut is critical. Some of the carrier assemblies are bolted in and come out as an assembly. Those need to be torqued properly, but won't fall out.
One of these is what I thought you were referring to.
Well all they replaced was a u joint, carrier bearing and rear seal. It failed right in the middle where the new part was installed which I thought was a carrier bearing. I know what a read seal is and a u joint is and the new part where it failed was not one of those.