About a year ago I replaced the passenger side IWE when it went bad and the problem was solved. I have read the threads on replacing and diagnosing so i am familiar with the issue.

Yesterday I came out out the hunting property and turned the 4wd off when I hit the pavement. I got a few hundred feet down the road when I heard the grinding clanking noise. I slowed down and noise went away and I was able to get home without hearing it again. I suspected IWE problem.

Here is the issue......I jacked up the truck and rotated the tires with the engine running. The drivers side worked correctly with no spinning. The passenger side spun the IWE shaft and was very hard to turn.

I disconnected the line so there would be not vacuum. The drivers side was able to spin but the IWE spun with it as it should without vacuum. The passenger side would only move forward and back slightly and the IWE was moving with it. It seemed to be locked in on the transfer case side. I was unable to rotate the wheel completely by hand.

I then connected everything back and had my wife drive slowly as I watched. The passeger side was rotating with the wheel. The drivers side IWE was rotating but in the oppsite direction just like an open differential would. The 4wd light comes on in the dash and the 4x4 seems to engage and work.

Is something not correct in my transfer case or is it another issue? Is it safe to drive the truck with or without vacuum? Thanks for the help!

 

The way I understand the IWE is that no vac=hub engaged.

Might want to check the vac lines for breaks/critter snacking.

 

As jgger has already said, no vacuum (ESOF switch off or engine not running) will lock the IWEs and thus connect your front wheel on each side to the front axles / differential through the IWEs.

What I didn't see in your post was if you tried turning the 4x4 system on and off. If you didn't have vacuum (for whatever reason), your IWE's would lock the wheels to each axle and you would be able to turn the axles with the wheels. Since our trucks only come with open front diffs, that would mean turning one wheel would make the other one go in the opposite direction. That would say to me that your IWEs are not seeing vacuum and thus locking to the axles. All that's left to have 4x4 is engaging the transfer case. If your TC was in 4x4 and your IWEs were locked, turning a front wheel would obviously be pretty difficult since everything was now engaged.

I'd check for vacuum at various places in your system starting at the IWE's and working back.

 

Drivers side appears to operate normally.

Passenger side does not work correctly and I suspect a vacuum problem on it since I replaced the IWE about a year ago. My concern was with the 4wd off and the vacuum line unpluged I was not able to rotate the wheel freely. It seemed to still be locked into the transfer case.

Maybe the truck just needed to roll a few feet to have the transfer case disengage? I left vacuum lines unplugged and drove it to work this morning. Nothing seemed to be out of the ordinary other than the shafts were rotating.

 

The IWE would lock up with the vacuum line removed. That would mean your wheel / tire / hub would be locked into the axle shaft - which is locked into the differential. Even if the TC was not engaged, you'd still have a bit of an issue rotating freely.

I'd say you might just have a vacuum leak on the one side. Remember though, a leak can cause partial IWE engagement which can wipe out even a brand new IWE.

 

Thanks for the info. I knew the IWE shaft would be locked to the hub without vacuum. I was just concerened about it not turning freely. The last time I had a problem I did not remember it being hard to turn. Hopefully it is just the vacuum and not the IWE itself.

 

If he is in 2WD, the transfer case is unlocked (front drive shaft), so even if he removes the vacuum line from one of the IWEs, he will still be able to rotate that wheel (lifted off the ground, of course). He will also be rotating the spider gears and the front drive shaft, so it will take more effort than simply spinning a free wheel on a bearing. That's normal.

I'm confused a bit by the OPs post- he says the IWEs are rotating- surely he doesn't mean the IWE is rotating, as the aluminum shell of the IWE bolts to the steering knuckle and cannot rotate. I think he means that the IWEs are locking the wheel to the half shaft, so that the half shaft rotates with the wheel. In 4WD mode or when the engine is off, there is no vacuum to the IWE, so the wheel and half shaft are locked together. In 2WD mode with the engine running, there should be vacuum to the IWE, and the wheel should rotate freely while the half shaft stays stationary. With all the wheels on the ground in 2WD, neither the half shafts nor the front drive shaft should spin when the trucking is moving.

To the OP- I would get a vacuum gauge and see how much vacuum you have at each IWE (only pull one hose at a time) at idle in 2WD. Then have someone rev the engine while you watch the vacuum gauge. The check valves, if working properly, should prevent the vacuum at the IWE from dropping when the engine is revved.

 

Yea, that's the way I read it too.

 

Yeah I meant half shafts are spinning. I am going to check the vacuum as soon as I can. Thanks again!