Okie dokie... Thanks everybody!

 

If you drive with the hubs locked and the TC disengaged, I don't think you will be hurting anything except your fuel mileage. And I am not surprised that you are hearing a little clunking when close to steering lock. That's just the u-joints being exercised.

With the TC and hubs engaged, a few things come into play. First off, to avoid driveline binding, the average distance traveled by the front wheels needs to be the same as the average distance traveled by the rear wheels, and it never really is, so that is why you only should be in 4wd on slippery surfaces.

As far as feeling pulsing on the steering wheel in a turn while in 4wd, there's something else going on. If you apply a constant speed of rotation to one side of a u-joint, the other side will turn the same constant speed, until you start to put some angle on the u-joint. Then things change a little bit. A constant speed on one side of the u-joint will result in a pulsating speed on the other, and the amplitude of that pulsing will become larger as the angle on the u-joint is increased.

This is the distinction between a u-joint and a constant-velocity (CV) joint. Technically, these trucks should have CV joints in the knuckles, but that is cumbersome and expensive and not typically really necessary due to the conditions under which 4wd is usually employed (i.e. slippery surfaces).

So when you are driving in 4wd and you turn the steering wheel, the drivetrain is trying to turn the front axles at a constant speed, but the u-joints on the ends of the axles, with some angle on them, are trying to turn the wheels at a pulsating speed (higher and lower during each revolution). This is the side-to-side tugging you'll feel on the steering wheel, and it will happen at even the slowest speeds.

The windup in the driveline that you get from the front and rear axles traveling different distances is a separate and distinct effect.

 

Wow! What KelVarnson said! He's go it nailed.

Rep points sent!!

 

Why thank you very much!

 

And even more rep points

The sound you here when NOT in 4x4 but with the hubs locked is the axles accelerating and decelerating, along with the spider gears in the diff. Which is also driving the ring and pinion back and forth...

If it can't take a little flopping around, and something breaks, it was going to break on you when you needed it anyway. Best time to find out is when you do NOT need 4x4

 

Thanks for that!

Ah yes, inertia... Excellent observation. I'd rep ya if they'd let me.