Everything you wanted to know about IWE and then some...

[seapong]

Correct me if I am wrong... So the the 4WD transfer case is only to switch between 4H and 4L gear ratios and the front driveshaft is always powered (locked center diff) and is up to the IWEs to engage and disengage 4WD?

 

[Huck]

Negative. Front diff is open until you hit 4hi or 4 low. Vacuum releases the iwe to engage in 4 hi or 4 low

 

[seapong]

Sorry I feel like I need to clarify my question... coming from a Jeep background, the concept of IWEs is sorta new to me.

Traditionally in Jeeps, the transmission output will drive the transfer case in the middle of the vehicle. All 2WD/4WD/4H/4L switching mechanisms are all contained within this t-case. A Jeep t-case will typically have 3 main components:

1. 2WD/4WD mode - In 2WD mode, the front driveshaft is completely disconnected internally in the transfer case. Rotating the front wheels will also rotate this free spinning driveshaft. Similarly in 4WD mode, the transfer case will engage the front driveshaft connected to the center differential to absorb engine torque.
2. a center differential - the differential to distribute power between front and rear axles that is only active in 4WD full-time or all wheel drive mode. This is what makes 4WD full time ok for pavement. in 4WD part-time (equivalent to 4H) this center diff is locked, distributing exactly 50% torque to front axle and 50% torque to rear axle. Note that this center differential in most models is not present anymore, therefore making any kind of 4WD mode only for loose or slippery surfaces.
3. Additional gears to drop in for low range - self explanatory

I guess my question here is, on Raptors, is the mechanism of engaging the front axle for 4WD completely dependent on the IWEs? thus meaning the transfer case connected to the transmission only has 1 purpose, to switch between 4H/4L and always providing torque to the front and rear driveshafts?

 

[Huck]

No. I'll say it again.

When in 2wd the wheels spin freely front axels do not. When you engage 4wd iwe engages and so does the transfer case

 

[seapong]

That answers my question thanks Huck


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[Yukon Joe]

That answers my question thanks Huck


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The purpose of the IWE is so the front half shafts do not spin with the front wheels when in 2wd. It's a gas saving measure.

Yukon Joe
www.RUNRAPTORRUN.com

 

[Wilson]

Might save gas but not the pain in the ass.

 

[heinzlester]

hello sirs

i want to ask about the clunking noise at the front end right side which i was experiencing with my 2013 raptor running over slight bumps on the road. my raptor has 67000kms on the odometer reading.

i figured it has something to do with front axle shaft moving causing the clunking noise and upon inspecting i found the iwe is already broken.

so i replaced it with a new one and expecting the clunking noise to go away but it didnt.

do you guys think i should replace the iwe in pairs? is the clunking noise caused by that? how do i check the hose for leaks?

your inputs will be greatly appreciated

thank you

heinz

philippines

 

[Yukon Joe]

Welcome to FRF. Iwe is a wear item and are typically the issue for the clunk and 4x4 issues. The vacuum selonoid valve can also fail. It's a cheap part and easy to replace. Should add one to your offroad tool box of you don't already have one.

Now, the vacuum system is designed such that if and when it does fail, the iwe is engaged. That way in a worst case scenario, your truck would have 4x4.

An easy way too test the iwe vacuum lines is to jack the front of the truck up to get both front tires off the ground. With the truck engine off, Spin the tires by hand, you should see the axle move when you do this. Each axle will move independent.

Now start the truck. Spin the tires again by hand. This time the axles should remain stationary. If they spin, you could have a vacuum leak.

With the truck still running, put it in 4x4. Spin the tires by hand. The axle should turn with the tire.

Let us know if you have any other questions.

Cheers,

@Yukon Joe
Drive your raptor here!!!!
www.runraptorrun.com
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[heinzlester]

thank you for the reply sir .
thats what i did this morning sir,
with the 2 front wheels raised and engine off. i tried turning the wheel ( both left and right) and the axle turns with it sir. when i start the engine , i turned the wheels again and both axles remain stationary . so i would assume theres no vacuum leak sir.

im just bothered by the clunking noise its making front end right side.

let me know anything sir

heinz