4wd questions

[Whiteshadow]

Dumb question, but I don't have the owners manual. How do I use the 4wd? Just turn the knob and go? Anything in particular I should know about it? This is my first 4wd vehicle. Tips/suggestions/advise?

 

[Bedrck47]

you can get a owners manual from

owner.ford.com

 

[jlo82585]

depending on year and if my memory serves me correctly it is as follows.

2wd - on early models they had a 2wd setting which just turned off the solenoid that controlled the T-case frt. output. Your diff.'s If I remember correctly are constantly locked and engaged so there is a very minimal MPG boost by running in 2wd

4wd / AWD - standard mode for most expeditions, this is primarily a 2wd system in normal conditions (20% to the frt and 80% the rear if memory serves correct). when wheel spin is detected in increases the amount to the front tires essentially bringing you into 4wd. however, in my experience the wheel slip sensors react pretty slow so if im going into mud or snow i always go into 4hi

4hi - this locks the t-case into 4wd with 50% to the rear and 50% to the front. there is a noticeable reduction in turning radius and MPG in this mode

4lo - Not 100% on this but I think in 4lo the T-case goes to a much lower gear ratio and all 4 wheels are locked meaning if one wheel is slipping the power will instead go to the wheels that are not until traction is restored. Very poor turning on pavement in this mode and bad MPG. top speed in 4lo Is between 20-40mph.

feel free to correct me on this, I feel like I may have just described the 4wd system of the HMMWV I used to work on in the army....

 

[Vigilante]

Basics on four-wheel-drive vehicles. This is a little old school, but it never fails to continue to do it this way. Before shifting into four-wheel-drive, pull over the side of the road and shift into four-wheel-drive from either park or neutral. When in for high, never exceed 55 mph. One, Because if you are driving in snow or mud you should never exceed that speed anyways. Two, it is easier on the entire vehicle. When using for low, never exceed 25 miles an hour. It helps you maintain control

 

[Bedrck47]

Hate to say this but when going from either 2WD or Awd there is no need to pull off the rode as you can shift on the fly as long as you are below 55 mph.
Now going into 4LO does require one to stop, shift into neutral with foot on the brake and then shift into 4LO

This is why I posted the link to the owners manual for the OP That way he will get the proper procedure that applies to his expedition

 

[Whiteshadow]

I understand the basics of 4wd, what I was wondering is this. Do I just select the option I want when i want it or when going from 4wd back to 2wd or awd, do I need to back up for a short distance to disengage the hubs? I have not d/l the manual yet, but thanks for the info!

 

[Bedrck47]

suggest you down load the manual and read the 4wd control operation, as that will be your best source to answer your question

 

[tojohnso]

Don't engage any 4x4 mode on pavement, ever.. Only on dirt, grass, sand, snow or similar surface. The only exception is going from 4x2 to AWD (or back) mode on vehicles that have that option. The hubs are not considered locking hubs so no need to reverse to unlock them. That went the way of the Bronco the expedition replaced (long live my '96). The low (4x4L) mode only drops the gearing so when you apply gas, the wheels won't spin as fast allowing more torque. It does not "lock" all four wheels. The differentials would need to be considered "locking hubs" that generally have a switch to engage for that to happen.

A really good site to read up on using 4x4 is (and I highly recommend reading it even if you think you know 4x4): http://www.4x4abc.com/jeep101/index.html

Note that if you ever go somewhere on "deep sand" ensure you reduce the air in your tires to a min of 19/20 lbs and down to 10-15 lbs if you are having a hard time. Even if you get really stuck, lowering the air can get you out.

Enjoy!