Yours will not/did not click or grind because it is not being used. You owned effectively a rear wheel drive truck with a switch/lever to make it 4x4. 99.9% of the time those trucks are in RWD mode, which means your cv shaft is not being used. It just free spins at most, transmitting no torque.

How long can it last like that? Basically forever.

Ah. I get what you're saying now.

That the wheel suspension and tie rods are the working components, absent power.

It definitely took more of an umph to get into 4WD late in life.