If you have the hubs locked in 2wd, you spin the cv shafts (I concur on the needle bearings), front differential, drive shaft, tcase output shaft, chain drive, and input sprocket part of the 2wd/4wd clutch. That's a lot of mass and a lot of wear. This is a PART-time 4wd system. Look at the "bearings" on the low speed loaded gear shafts. I drive in 2wd until I'm almost stuck.

I never had a problem with my autohubs unlocking once engaged, in rocking maneuvers, reversing, or anything, but I carry a pair of manual hubs along, JIC.

Not responsible for advice not taken...