The purpose of 4WD is limited slip. If it's not, you have a problem.

Ford front differentials, with a few exceptions, are not limited slip, they are open. Also, with a few exceptions, transfer cases are either in or out, not limited slip.

I am reminded of a buddy bought a new truck, claimed it had all 4 wheels pulling all the time because it was "full time four wheel drive", and it did if all 4 were on sound footing. I told him he should watch where he takes it. He scoffed. I challenged him to pull up on yon snow patch and just put one wheel on the snow, the other three on the bare pavement where snow had been cleared. I hooked my car via the hitch and a snatch strap to it, he tried to move the car, his truck just spun the right front tire and set there. I even let off the brake and the car started moving the other way dragging his truck as the car was on a slight grade. His right front just spinning on packed ice like snow. It was funny.

Fix Or Repair Daily - IWE Manual override
 

[QUOTE=tbear853;4139409]Removing the hoses and capping the ports and lines to prevent ingestion of water, etc .... wil not hurt anything except gas mileage and kill some small bit of acceleration, as you are introducing drag.

You will cause the IWEs to engage and stay engaged which will then cause the front axles shafts and front drive shaft to turn at road speed. The 2 hi will still be 2 wd, the 4 hi and 4 lo willl still engage and dis engage, you just won't hear the IWE's engage ... or wait for same. If run on hard pavement, you will still have to maybe stop and back up to relieve loading to get out of 4 wd into 2 wd.

You will wear the front CV joints and shaft universals and bearings more, they may still outlast the truck?

As pointed out, the front end will see life just like the front end of a Harley or Limited. There's no added stress on a part time transfer case, the connection from transfer case to front shaft is open as long as the motror swithed it back last time. In 4 wd the transfer case would see life same as stock.

The full time transfer case just has an added "differential" of sorts between the front and rear drive shafts to allow for thier turning different speeds which happens because of different tire loading / air pressures / turning radius (front end has to travel further around every turn).

What I'ld be interested in doing is come up with a way to easily use the 4 Lo position without engaging the IWEs. For those times where you might want to pull a heavy load slowly up a paved steeply graded driveway or hill (like going up Grandfather Mountain). Maybe a camper, maybe a trailer loaded with firewood, where you would enjoy taking advantage of the lower ratio in the transfer case so to go up at low throttle while not beating the hell out of the transmission.

I can do this with my '77, it has manual hubs. I'ld be pleased to have manual hubs on my '07 ... I know enough to not be running it full throttle in low.

Any ideas out there?

Bypass the vacuum valve on the firewall either electrically or mechanically. A switch on dash to manually engage/disengage IWE - Three position switch: ON; AUTO; OFF.
Very good and functional idea. I use 4L to pull my boat out of the water and always worry about it tearing **** up. It would also be nice to control the rear end clutch pack as well. One thing at a time...

Found this Technical Service Bulletin that directly addresses this issue. https://static.nhtsa.gov/odi/tsbs/20...81917-0001.pdf

Recommended fix is to remove and cap the vacuum supply lines.

That article only applies to vehicles that have a "4A" option in addition to 2H, 4H, and 4L.

I.W.E.s Full Time Bypass
 

IWE's are for reducing cv damage at high speeds so if you use the expressway or cruise at higher speeds often, I would not recommend full time engage bypass on them !!