What transfer case are you working on? Are you sure you're supposed to take them out and leave them out? That sounds a little odd to me. When installing the Tom Wood SYE in my 242, the needle bearings fell out when I removed the mainshaft, as the instructions indicated they would. During reassembly, they needed to be temporarily held in place on the shaft with a thick layer of grease until the mainshaft was slid back into position. I would really imagine you're supposed to re-install the bearings, but if your kit is for something other than a 242 I have no first hand knowledge.