I took a 99 F250 Super Duty for a test drive this past Saturday. Took it off the road on some sandy roads. I did air down the tires, but only did so using my eyes (did not have a gauge), but wasn't too worried because these roads were not that sandy. I proceeded to get the truck stuck. Buried the rear axle almost. I have a fair amount of experience beach driving, and never get stuck with my Wrangler. Before hitting the sand, I put the truck in 4WD Hi.

It has the Auto front hubs, with manual override.

While I was trying to get out, someone noticed that the front wheels were not spinning. Only the rear ones. Once I dug the truck out a bit, I put the hubs in the Lock position, and was then able to drive out.

I asked the truck's owner, and he insisted that the 4WD works. We did a spin test on a dirt road. Punching it in 2WD you feel the read wheels spin. In 4WD (back in auto), the wheels did not spin out.

Since one of the main things I want this truck to do for me is to take my surf fishing on remote beaches, I need to know that I will not get stuck.

So I have a few questions. Thanks for reading.

Does the front wheels not spinning when stuck in the sand mean that the 4WD system is not working, or would they not spin due to some sort of traction control?

Is this truck just too heavy for sandy driving? Or is airing down properly the key?

Any other way to verify that the 4WD is working?

 

So were the hubs not locked when you got stuck?

Lock the hubs, put the truck in neutral, drop into 4Lo, put it in drive, hold the brake to the floor, give it gas. If the 4wd is working, you'll roll. If not, the rear wheels will spin.

 

I will try this trick.

Maybe I just showed my ignorance. The seller implied to me that you did not need to manually lock the hubs. That you could leave them in Auto and you would then change to 4WD by using the switch on the dash.

When I got stuck, I had not touched the hubs. When I did lock them down, I think I noticed a big difference.

So do you have to lock the hubs by hand to use 4WD on this truck?

Thanks for the response.

 

I don't know about that system too much, but I generally don't trust "Auto" settings.

 

The ESOF (elxtronic shift on the fly) system in these trucks are probably the most troublesome systems known to any driver. They can leak and prevent the system from working, and they can leave you stranded just like you mentioned.
OK lets understand the principles gehind the ESOF system and how it works.
In the AUTO setting the front lockout has to rely on a "pulsed" vacuum signal that engages the hub itself. Now, the wheel actually has to match the axle speed in order to engage the locking assembly. This is difficult to do without rolling the vehicle. If you are already stuck, you could get lucky and the front end will engage, but dont count on it. Very seldom does it ever work this way and the majority of the time, you end up in an embarassing position.
If you plan on needing 4wd, you should always engage the front hubs to the lock position, and verify that the hub has actually engaged. I usually turn the axle stub by hand from the backside of the knuckle to verify, or I spin the dirveshaft to see if it turns or not.
The same is done for both sides and I do this to verify that the front hubs have unlocked once I am done wheeling. You would be suprised at how many stuck lockouts there are out there. Its not a matter of "if" it will not work properly but "when". I have yet to see this system function properly, especially if they get used too much, or used very little. Too much and dirt contaminates the hub assembly, and if you dont use then enough, they seem to stick and leak so they may never work well.
Ok, so we have them locked, and now we can rely on the dial inside of the cab to operate correctly, and if it does, you will have a direct connection to the front hubs every time and when you call the 4wd system, it will work. Thats simple.
Verify that the hubs actually unlock once you move the dial to the auto selection and disengage the transfer case. You should be able to turn the front axle stube one by one to verify.

In any case, buy some manual locking hubs and forget the frills of the auto stuff. Might work once in a while for wet soccer fields, but if you need your system to work every time, go manual. You can be sure that when the dial says "locked", its locked, and when it is the "free" selection, that you are indeed free.

 

Thanks for that info! Is it the case that if the ESOF system is working, and you change the dash from 2WD to 4HI, that the hubs will rotate on their own from AUTO to LOCK? That is, is it enough to engage the ESOF 4HI and look at the hubs to see if it works?

It sounds like you're saying that if I anticipate needing 4WD, I should lock out the hubs to manually to LOCK and then drive in 4WD. If I have the hubs locked manually, does it matter what the dash is set to (2WD, 4HI, 4LO), or do I still have control over 2WD or 4HI using the dash?

THANKS!

 

You can still have the dash **** in 2, 4 or 4L position with the hubs in the lock posion.

 

If u manually lock the hubs u can use the dial on the dash to switch between 2, 4 and 4 low.

 

You have great information above.
Lock the hubs in and unless you have selected 4wd you are not in 4wd. You simply have the front hubs engaged. Its not until you select 4wd high or low that you will actually have 4wd.
By all means lock the hubs when you decide that you may have to engage 4wd and when that time comes simply hit the switch. Know that the low range engagement can be tricky and may not engage if you are stuck in a hole.
This is one of the reasons that the ESOF system is not desired.

 

That's electric shift stuff is crap, but u can still get a lever on the floor to shift and manual hubs on those pickups. My Dads 08 is that way, it even has leather seats. So its not just a work truck option. On that system u have to lock in the hubs to use 4 wheel drive.

 

That is a gray area. While a manual system is possible it is not with an ESOF, or ESOS system. One cant modify the electronic case to accomodate a manual lever. One can shift it manually with a wrench but know that the elctronic cases are different.
Want proof? Look for a neutral position on a electric case. It does not have one. Full manual provisions require a different case.