I have a Strange 12 bolt rear end with a Yukon differential. I'd like to swap it out with an Eaton Posi unit. Does the pinion gear need to be removed or can the main part of the differential(posi and ring gear) be pulled out after removing the axles but leaving the pinion assy in place?

 

Why yes, yes you can.

 

After you pull the axles,check/record the 'lash' to be able to return to that 'lash' with the replacement carrier.