I know there are 5 billion IWE threads and i think I've read them all (and they have helped tremendously!!) but I have another issue that I can't find answered anywhere. I had issues with my system several months ago and replaced the solenoid with the updated version with the rain shield and thought I had fixed all issues. Here in the last several weeks I've noticed the same noise but it only happens at speed, usually on the interstate. It never happens just driving around under 45mph, it seems to only happen after the transmission goes into overdrive. My first thought was that the actuators were bad so I ordered 2 new ones and I replaced the passenger side first and took it for a test drive and it's still doing it, even on the passenger side. I have checked the vacuum line and there are no visible holes but I guess my next step is to replace the vacuum line. Is there anything I am missing that y'all would check???

Again, everything works as it should 90% of the time, this only happens when I'm up to speed and usually only in OD. 4wd works as it should as well. I know I'm losing vacuum somewhere I just don't know what else to check. I'm going to replace the drivers side actuator since I already have it but I don't think that's the problem since it's still trying to engage on the passenger side. Thanks for the help, Matt

 

test your vacuum system. Rent a cheap gauge (free rental usually) from some place like autozone, checkers, etc. Pull vacuum on your IWE hubs and see if it holds. Then pull vacuum on the hoses to see if you are leaking down there. You might have a pinhole somewhere, but unless you do some testing you are just shooting in the dark.

 

Inspect the inline check valves and your vacuum tank. I used this for the large valve that T's off the brake booster line: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
And these for the two smaller ones:
https://www.amazon.com/dp/B000C5HZ24...I2B7SIM2H9I2WG
The later models have 3. There should be one near the IWE solenoid, and one near the vacuum tank. Blow through these by mouth to see if they only work one way. If not, they are bad. Vacuum check your reservoir (located behind the battery) with a Mityvac.

 

The dealer couldn't replicate mine so I fixed it in my garage. It was the check valve that runs in front of the brake booster. It was very intermittent so I actually removed the check valve and used a vacuum pump on both sides as soon as I switched the flow it let loose. $5 at autozone and it was fixed; this was after it spent 2 days in the shop and cost the dealership my rental and their time. I still need to go back and bring them the old valve.

 

Sorry forgot to report back that I did get it fixed. Mine ended up being a small leak in the line up by the reservoir. I had forgotten that several months ago the line had split in two and I had "fixed" it with some rubber hose that I put over the line. I guess that worked for a little while but slowly worked itself slightly loose so that it leaked intermittently. I just replaced the line going from the reservoir back to the solenoid. Luckily that was the first thing I checked and my next step was going to be renting a vacuum pump

 

Renting the vacuum pump should of been the first thing.. you replaced 2 IWE's for no reason. Glad you got it fixed.