I doubt you're going to be able to buy just the front output housing so if you're talking cheapest, it seems like either approach will be about the same since cost you'll have to buy an entire transfer case regardless.

 

 

My build date was March 2001 with CDL.

I would replace the entire case. I think it's been documented on this site that replacing just the front nose and associated CDL hardware is a bit of a pain with the transfer case still in the vehicle. A hundred dollars for a transfer case is CHEAP. If you want 04' factory linkage to activate that CDL, your looking at around 300 dollars! If you off road at all, it's a must.