I have a 2015 f150 3.5 eco with a 6" lift and was getting some growling sounds out of the front so been having f150's before I assumed it was the iwes so I changed both and the check valve and the solenoid just so I wouldn't have to fool with it later. Truck is still growling any speed over 50mph. I put a zip tie on my front driveshaft and it is turning all the time which I know it's not supposed to be. I removed the front driveshaft and now the growl is gone and I know for sure nothing in the front is spinning with out it.
Is there anything I can check in the transfer case that would make the front drive shaft keep spinning? It doesn't seem like it spins as fast as when it's in 4x4 as it does when it's in 2wd
I will bring it into the dealer but if it's something I can check fairly easy I will. Thanks

 

Removing the front shaft removes anything from keeping the half shafts from spinning. Meaning no resistance. So, they could still be spinning with the wheels and not get the grinding since there is no resistance. There is always a part of the TC that is spinning to my knowledge until the motor shifts to engage the front shaft.

Have you checked the lines? Especially the connector on the frame where the rubber hose from the IWE connects to the plastic lines? Could also be the front diff making the noise also.

 

It's not the front. I have done vacuum tests on everything, leak down test, and after removing the front driveshaft I have confirmed nothing is spinning while driving the vehicle. It's absolutely the front shaft being powered

 

What's confusing why you think the noise is the TC when the noise stopped. If the shaft is being powered, the noise would continue regardless of whether the shaft was connected or not and thus the noise would continue. Unless the front being connected provides just enough resistance to make whatever slip to cause the grinding noise. Not sure but, I'd think you should be able to turn the output shaft by hand to see how smooth it is. You could also drain the fluid to see if there is any metal in it. That would definitely tell you if it is eating itself up.

 

It's not grinding noises. It's a howling noise. I have an aftermarket driveshaft on. It is clocked right with a double Cardon joint. The noise is coming from the driveshaft being partially powered from the transfer case which is turning the draveshaft, transfer case, and cv axles. It's not turning the tires because the vacuum system has the iwe unlocked. I have looked over everything. I am positive this is the problem just have to figure out why the front driveshaft is partially engaged.

 

I am picking up harmonics over 50mph in 2wd yet everything minus the wheels are being spun by the front driveshaft.

 

Then if it was me, I'd see how easily the output shaft of the TC spins by hand when truck is in 2WD. If it feels gritty or not smooth at all, I'd dump the fluid and check it. Then, based on what I see there would determine next steps.

 

Pull the TC shift motor and then manually shift the TC into 2wd mode. See if it still spins. This will eliminate every electrical component including the TC motor. Then you will know if you have an electrical/module issue or a mechanical issue.

 

The front driveshaft spins freely when it 2wd and doesn't turn while moving the truck in the driveway. It starts to turn after about 5-10mph I tested this with a zip tie tied to the front driveshaft where I could hear it spin and hit my kicker bars easily

 

I may just bring it in. But I know the dealer is going to point to the iwe first like I did