That's a slippery slope, "While I'm in there". Since you are dropping the trans you might want to do the axles, maybe the transfer case, maybe the guibo, and depending on the mileage perhaps a rebuild of the trans.

Seems like it's worth confirming the need before starting all that work.

a small inspection camera could be fit up there to take a look
Or pull the starter and check with a mirror.

ill borrow a friends borescope & l@@k through the bottom holes of bell housing. also double ck the valley pan & coolant pipe o-rings.