The auto locking hubs are a great idea, if they work. If only one engages, or, only one disengages, you aren't going to know that, unless you check. Yeah, I have had both happen. How do you know, unless you get out and check, or you are servicing your truck, and you can't turn the axle to hit the upper ball joint zerk?
Its real interesting too, when you hit the ESOF, expecting to get 4 wd., and you have three wheel drive, or you are still in 2 wd. I don't care if you are driving down a slick, snowy, icy road. When you hit the switch, you should get what you called for.
Its the same when disengaging it. When you turn it back to 2 wd., is what you should get. If not, you may get partial disengagement, and now we are grinding one side, or the other into powder.
This whole wonderful system is based on a vacuum hublock solenoid, an air tank, and bunch of vacuum lines, coming down from the vacuum tank, to both front axles, that are controlled by a very expensive seal, in the back of the hub, and its a pain to work with, or replace, and a large 50 cent yellow o-ring.
Any one of these components fails, half or all of your wonderful, never have to get out of your truck, system fails. To be exactly right on it, you have to get out anyway, and check it. So, what is the difference in getting out to shift the hubs in, or out. Unless you have the money to throw at the system.
I have lived with 4x4 vehicles, since the late 60's. With all the the wonderful systems that automaticly shift the hubs, in an out, I have never seen one that is even close to foolproof. You still have to get out, and check. Or, you are wearing, grinding your hubs to pieces. Its entirely your call. I am sure, when I turn my hubs in. I am also sure, when I unlock my hubs.
Parts are way too expensive for me to wear them out, because I am unable to get out of my truck. As I said, in my first post in this thread, the F-450, 550 do not have self-locking hubs. I wonder why that is? Cause those are really work trucks! Are our trucks any different? I don't think so.
Also, why did Ford put manual locking hubs on our trucks, in the first place? Ford, the company that wanted to save 4 cents per transmission with the wonderful mechanical diode one way clutch. We all know how that one turned out.
Sorry for the rant, but, when the system doesn't work, you may be the second person to find out for sure, when you take it into the dealership, and they give you a $1500 repair bill because of the strange grinding noise in the front end.
"White Moose", 2001 F-250,XLT,Auto, Super Cab, 4x4. Early PSD, build date: Aug. 16, 2000, no PMR. AIS, AIH delete, Zoodad, CCV mod. (not any more), BTM, GOS headlite harness upgrade, harpooned fuel tank, B&W gooseneck hitch, Firestone air bags. 6.0 Tranny cooler, pillar mount, with Isspro pyro, boost, and tranny temp. Trailer Towing Mirrors, Bilstein Shocks, 03 Clear Headlights, HP Crossover line, DP Tuner F-5 switch: High Idle, 20 hp. tow, 40 hp. tow, 80 hp. tow, 80 hp. econ. drive thru. 200,000+ miles and still running strong. No mech. diode tranny. Changed to the 2002 model ,before it left the dealership. 25 ft. 24k Horse Creek, flat bed gooseneck.