JimmyDee
God Bless America
I will assume that you have non automatic locking hubs. If they are automatic, you have to do nothing.I do have a locking front differential. Detroit.
As far as the steering, I've only locked my hubs once. I wasn't able to move the steering wheel much after rolling a few feet forward. I didn't put much 'oompf' into the turn, because I wasn't sure if the steering wheel resistance was normal, so I just got out an unlocked the hubs.
Without being certain, I decided to skip the whole idea.
The hubs do what has been said, lock the front axle to the wheel. I have driven an entire winter with them in lock. It hurts nothing except for the gas mileage. On the truck I did this with, it cost about 4 miles to the gal. Gas was cheap then. If your hubs are the non automatic and locked in, you should be able to go in and out of 4x4 at just about any speed without hurting anything. Everything is running at the same speed and should go in and out of 4x4 easily.
With the automatic hubs I have found I would prefer not to be going any faster than 5 MPH. I have been told you can do it faster but it makes a loud clunk that I don't like. I equate clunk to damage.
Never drive on dry pavement in 4x4. The drive train will bind up and could cause damage to the system. I have also heard that it is not advisable to drive in snow greater than a few miles per hour but I have had a 4x4 since 1969 and one of the reasons I have one is to be able to drive 50 mph on the highway with it snow covered. Many times I have driven the 35 mile drive to Grand Rapids in 4x4 at 50 - 55 mph with no ill effects at all.
Jim