Where to get a front pump for a 42RH (A500)

I'll have to see, it may be a bit before I get the chance to pull the trans. The truck still technically runs and gets used pretty often, so I'm not sure how long I can have it sidelined. On a different note, does the 4x4 have any bearing on the transmission? Didn't know if the tailshaft section was different to bolt up to the transfer case or not. I assume the internals would probably be similar, but figured it never hurts to try to double check everything before ordering.