After thoroughly cleaning the case and all of the parts, it was time to put the idler gear assembly back in. It takes a bit of patience, as you have to support the gear, hold the bearing and make sure the shims don't fall out while you slide the shaft into position. Once the shaft is in, the nut on the front of the shaft located on the front of the transfer case can be tightened. After that is accomplished there should be no front-to-rear play in the idler-gear assembly. The end of our shaft (seen here) was below flush with the case after being slid in all the way. If it is not, there may be some play in the gear assembly, so make sure the shaft is all the way in.