Larry, you should not need a tool to install the output's on the transfer case. The axle's pinion shaft to yoke fit is definitely tight (or should be). The yokes to shafts on the transfer case, should not be that tight. They do get stuck on there once their torqued, and may require a puller to get off. You should be able to get the yoke on sufficiently to start the nut on the transfer case to install them however.

I am not aware of any tool to install the yokes.