broken differential

I have a 2019 XRC Turbo with smartlok. When switching from 4WD to 2WD its recently developed an issue where it indicates on the dash that it has successfully switched to 2WD but when I hit the gas its still clearly in 4WD, it then switches over properly maybe 10 seconds later. Is my diff on...

Does anyone know where to buy just the front differential housing. It is not labeled in any exploded views as a part. Part shown below. Two of the bolt bosses that mount it to the vehicle snapped off mine and I would rather not buy a whole new front differential. Any information will help...