I have read IWE threads for years and I am thinking I have some sort of problem with mine now. When I am driving very slowly (<5 mph) I can hear a low rumble noise coming from in the front end. It oscillates, and appears to be related to my speed. When I switch to 4A or 4H the sound disappears, and then reappears when switching back to 2H. The truck is scheduled to go to the dealer next Friday. Any experience or ideas? Also, would you drive in 4A until the appointment at the dealer?

A little background on my front suspension-
-2015 F-150 with 40,000 miles currently
-I had a 2" level "puck" installed at about 3000 miles.
-I had the full suspension replaced (Fox 2.0 coilovers and shocks) at approximately 15,000 miles, over 2 years ago.
-The low rumble noise began about 1 month ago. I thought it might be related to uneven tire wear (BFG KO2's with 37K miles on them).
-I had the tires rotated 2 weeks ago, and the sound remained unchanged.

Thanks in advance.

 

The first thing I'd do is to replace the vacuum check-valve on top of the vacuum brake reservoir... if you don't have the latest one, which is blue. But I've read somewhere here when truck is lifted, you put a lot more stress on U-joints and IWEs (from the steeper shaft angle), so owners need to expect having issues a lot sooner. Will let an expert chime in if true or not (and if true, at how many miles), but makes sense to me, especially at 40K miles, so it might not be a vacuum issue from the lines or check-valve. Good luck.

 

Check for cracks in the vacuum lines. Since you had a lift, I'd start down by the wheels and pay special attention to the connector that connects the rubber line from the IWE to the plastic vacuum line up on the frame. If the place that installed the lift let them hang from the lines, a good chance they cracked the connector or the line close to it. It's also possible that they damaged one or both IWEs when they put everything back together.

Don't drive it with it grinding. Drive it in 4A or disconnect the electrical connector from the solenoid while driving and not diagnosing. This will keep the IWEs engaged and save your bearings from getting contaminated from ground material given off when he IWEs grind.

 

UPDATE:

I tested the symptoms yesterday, and they did not appear to be as obvious (i.e. the rumbling noise is not as loud), and also they did not seem to be 100% related to 2H vs 4A/4H (i.e. they did not always disappear when engaging 4A/4H).

I changed the IWE check valve as suggested in other IWE threads, and the symptoms were unchanged.

Any ideas? I am still taking the truck in on Friday to the dealership to have it checked out.

 

Did you check the lines like I suggested for cracks?

Could be solenoid as that was the number one item before the check valve if the lines are fine.

Could be the IWEs themselves. One or both. Again if the lines are fine.

If not them, then it could be the front diff or TC if still related to the 4WD system.

However, before assuming the last suggestion I’d look for loose heat shields or a rock or something on top of them.

Could be a wheel bearing(s) also.

 

I'm thinking wheel bearing beginning to fail. Does the sound change as you turn one way or the other? Since you're taking in Friday, please let us know what they find.

 

Have you taken the front wheel and tire off ? Did you check the inner rim of the wheel and when remounting torque the lug nuts to oem specs ?

 

https://www.rcvperformance.com/rcv-u...150-04-up.html

80,000 miles and counting no issues and 100% reliable 4x4 when i need it, dump this garbage vacuum system. You'll lose around .8 mpg and won't be sorry.

 

How does this thing seal to keep dirt and water out the hub and bearings?
BTW, same thing can be accomplished by simply pulling the power on the solenoid, for free.

 

Contacted RCV and they said they have never had a contamination issue. The wheel bearing is sealed and the little needle bearings are well covered by the CV shaft. The ring goes against the bearing and the CV joint.

Yes, pulling the lines and capping off is essentially doing the same thing as an IWE Eliminator kit except for the spline coverage having greater reach with the sleeve kit with a stronger material, and this is what I was after.