During a recent snow ( 6 to 8 " ) I got stuck in my own driveway. Then I realize the 4WD is not working. The hubs have been set on "Auto" for quite a while and in the past all I have done is turn the selector switch to the position I need and 4WD is activated. Tried hi and low range but could not get the front wheels to hook up. Tried repositioning the hubs to manual. Could not turn them by hand. Later after digging out, I backed the truck up for a city block while turning the wheel back and forth. No help. Hubs still frozen in the auto position. The book says that the amber light (4WD)will illuminate when the switch is placed in the high 4WD position, which it does but when switching to low 4WD no lights come on. Should have " low range " light according to the book. I hear a relay or solenoid clicking somewhere when the switch is moved from off to 4WD. This truck barely has 40k on it and I have already replaced the transmission ( out of warranty ) and now am concerned this may be another big expense. Any help would be appreciated.
Thanks, Marv

 

It's pretty common on the SDs to have the hubs fail. What year is it? If its pre-2004, you toss in Warns and you're set forever. If its after that, you have to replace the autos, then do some work in the engine bay, but end up with the same result: manual hubs. There are some threads in the first few pages of the SD forum that talk about this exact situation.

Are you putting the tranny in neutral before you shift to 4Lo? That would help.

Welcome to FTE bud Just in general, the more details you give, the more people can help you, and searching old posts before you ask a question can help you nail down a more specific topic, or even get you an answer faster. And keeping the thread title specific helps people crusing the boards find topics they can help on. Rock on, hang around, and lets get your problems solved

 

Bryan, thanks for the reply. Being new to this forum I mistakenly thought that if I have all the truck particulars listed with this forum in my preferences that they would automatically appear when I do a reply or post. Anyway, 1999 350 Lariat V10 with no modifications except a K&N Filter. I use this truck mostly to pull a 27' travel trailer. And yes the few times I have used 4WD I have been stopped when I select Hi or LO in either neutral or park. Are you saying that if I can't budge the hub selector on the wheels that they must be replaced? I am retired and don't have a lot of money to spend on this truck after the nearly 3K$ I spent replacing the tranny. Any thoughts you have about the wording for the title of this thread would be helpful. I just wrote what it is doing, "does not engage".

Thanks again, Marv

 

Aloha Marv,

In this particular case search is your friend. You'll be reading for days!

But to answer some of your specific questions:

You can sometimes use WD-40 (or similar) and spray it inside the edge of the selector you are trying to turn. This can free up the selector sometimes. It has worked for me in the past.

I would search for something like "transfer case relays" so that you can find, inspect and test your relays.

I would also look at this site to show how YOU can repair/service your hubs It'll save you a bundle! Welcome to guzzle's Ford PSD Maintenance Web Page

And, like Bryan was telling you, make sure your are in Neutral & your foot on the brake to go into 4LO.

Sounds like your biggest concern is the hubs not actuating. You'll find that there are a number things that can contribute to that. Broken vacuum line, pump bad, bad seal in the hub etc. etc. Get the manual selector turning and you should be good until summer so that you can tear into it.