Hello,
I just bought my first truck... 2008 F250 and I'm not sure about the procedure to switch from 2 wheel drive over to 4 wheel drive. Specifically, what position should the hub be in (free or lock). I could not find instructions in the owners manual. If anyone could list the step involved I would really appreciate it. Thank you.

 

I'm pretty sure that it's the same as with the 6.0L's. If the hubs are in free they are engaged by vacuum when you shift the **** to 4x4 and don't spin the front axles/driveshaft when driving in 2wd. If you have them in lock the hubs are already engaged causing the front axle/driveshaft to spin and the only thing that is affected by taking the **** to 4x4 is the transfer case engaging the front driveshaft.

 

If your rig has the switch on the dash, it should be as easy as turning the ****. Do this at low speed coming to a stop( give it a couple car lengths) and It should be set when you need it to take off again. You should turn it off under 40mph or so, at a steady-not increasing speed with no load or slowing using the drive train(engine ) to do so. While braking can cause binding if a tire slips but in normal situations while braking should be fine as well.
Your hubs can be in the free position if you have the switch on the dash although you may find the system more user friendly in on and off again use buy turning both wheel selectors to the lock position. This takes a step in the system out of the automatic process, but the front drive axles and drive shaft spin constant with the wheels and will drain on mpg do to some rotating resistance. 4L(last position on switch) should be left alone and not engaged until you find the owners manual section that details its use. Its great for pulling down houses and trees, stuff like that.
I have only touched on the full use instructions, so please search for original factory documentation. Others should be along in short order to correct anything Ive reluctantly typed here. But don't travel on pavement wet or dry( in 4WD) for any distance as it can, due to tire side wall height (wear or tire pressure) cause the system to bind and release harshly, or be damaged. Turning (semi sharp) in 4wd should be done on loose surfaces(sand, gravel,snow,ice) only. There is quite abit to the actual use, that those that have become comfortable with it, do without much thought. Enjoy, but remember, it doesn't help you stop.