I have a 2010 f150 fx4 5.4L. My question is when I go to drive my truck sometimes I get the grinding noise. Doesn't always do it but does it randomly. Goes away once I switch to 4wd and back to 2wd. Changed the solenoid and will still do it randomly. Know this has been talked about before just seeing what others think before I try and go replacing the actuators. Thanks

 

The IWE has been blamed for all sorts of problems, but it's actually a pretty decent part of a pretty well designed system. That said, things do wear out over time and your IWEs are no exception. Replacing the Solenoid seems to be the most popular "cure" for all four wheel drive issues, but it's not always the correct thing to do. Yes, if the Solenoid goes bad, your IWE's will very likely struggle to engage / disengage, but the real problem could be a bad IWE. Or, a bad Solenoid - left unrepaired for too long - can damage an IWE beyond repair.

So here's my thoughts. The Solenoid and Vacuum Lines are pretty cheap. Make sure those are in good shape first. Then, if they are, take a hard look at replacing both IWEs if you're still getting grinding noises. I changed mine when one of my IWEs went bad and it's not a bad job at all.

 

I recently started getting that grind from both wheels when going up hills. I think the consensus is a leak in the vacuum lines when the engine is under load losing vacuum. I ordered a vacuum tester to check them. This thread was a great help and you should look at it.

​​​​​​​http://www.f150forum.com/f72/how-diagnose-your-4x4-system-esof-186872/​​​​​​​

 

subscribed

 

Starting to get the same out of my 14. Keep us up to date please! And thanks!!!

 

I did a bunch of vacuum tests on mine. Ended up just replacing a $10 check valve up on the driver side firewall of engine. Took a whole 2 minutes to swap it out. Read the link I posted earlier. Unfortunately I had the problem driving thru the mountains on step hills during a trip. Now that I'm back on the coasts, no mountains, but I haven't been able to replicate the problem on interchanges/overpasses and other inclines.

 

That's the valve next to the brake master cylinder correct?

i referenced that yesterday. The TC checks ok, front hubs act according to instructions so no problem there. Similar issue for me being wot I've gotten a grind out of the truck twice in the past 3 months....owned the truck since July of 14.

 

On my 2010 5.4L it's on the driver side firewall, which wad changed from the previous model. Not sure if it's in the same spot of the 5.0L and ecoboost engine. Find the air lines coming from the iwes and follow them into the engine bay. Mine had three air lines going into a T connector.

 

I went ahead and bout a handheld vacuum pump....put vacuum on the line that comes out of the bottom and no loss of vacuum. Now I connected it to the bottom of the 3way check valve and slowly lost vacuum. So I guess it's safe to say that the 3 way check valve is bad?

Are re there any other check valves on this or....?

 

You can barely see the baby blue line but that's the valve I checked the bottom of going against the flow of vacuum.

Not my image but it's a reference.

 

Yup, same setup on my 2010 5.4L. I didn't see any other check valves on mine, I believe they changed from multiple to just the one for 09 and up, because that one check valve goes to both Wheels.

​​​​​​​ You can also hook the pump straight up to the actuators and see if they lose any pressure, pump it up to about 15 to 20 psi and see if it drops, I believe one PSI drop a minute is within tolerance per the other thread. you can also test the reservoir make sure it's not leaking and can hold a vacuum.

 

if I tested from the bottom of the Check valve to the hubs and didn't loose vacuum then in theory everything is intact correct?

also when you say reservoir....are you talking about the brake booster? If so what's the process in testing that. Thank you for your patience, learning a lot about this front end as we speak!

 

I believe the reservoir was that middle line that goes to that box. Test it the same way with the pump, it will just take a lot more pumps to get the vacuum up.

​​​​​​​ and I suppose that makes sense about testing from just below the test valve and it holding pressure. You can also take the check valve off, make sure its only allowing air to flow one way.

 

so I may have found the problem.

i vacuum checked the box at 20in lbs of vacuum and no drop. Re tested the line from the bottom of the check valve to hubs...same amount of vacuum and no drop. I had a slight drop in vacuum from the vents but less than half a in of vacuum.

but I can draw air through check valve from bottom so....? Is that the issue?

 

If you take it out, you should only be able to blow thru one side. I would assume the air flows toward the engine only, to the vacuum canister/engine, and not to the hubs.