What is that whine?

[shelby987]

I swapped my front axle about a year ago or so, the primary reason was an accident that left me without front brakes, so I upgraded to a corp 10bolt front with a locker. Today was the first actual day that I actually got the truck out on the road and had cause to use the 4wd.....while driving the truck very slowly out of the driveway, I heard a loud whine.....so I drove the truck to a nearby parking lot, I tried driving with one hub lock, then the other......but hubs seem to be easy to lock, but very difficult to unlock (even on flat ground, no load on the axle).....the noise didn't change with one, the other, or both hubs locked.

Could this noise be the hubs, the gears them selves, or is this just a normal noise to hear from a locked front end?

Also, my truck is a 250 with some upgrades.....pretty torquey, never had a problem in 2wd spinning the tires....but it seems to bog under the stress of 4wd, could this show that something is bound up, or is it just because the engine is under that much more load in 4wd?