Intermittent 4WD Grinding noise

[vanessa june]

Hey folks, a few days back I started experiencing a loud intermittent grinding noise in the front end of my vehicle. From doing some research and ruling out any other possibilities like loose hardware, something dragging, etc, I figure it’s from my four-wheel-drive attempting to engage. I have to jump on the highway in a few days to drive a few hundred miles and I really don’t have time to do an in depth fix, so does anyone know if I could I possibly disconnect and cap the vacuum line that’s responsible for activating four-wheel-drive and just disengage it entirely for now? Would I still be able to drive normally?

 

[99WhiteC5Coupe]

Hey folks, a few days back I started experiencing a loud intermittent grinding noise in the front end of my vehicle. From doing some research and ruling out any other possibilities like loose hardware, something dragging, etc, I figure it’s from my four-wheel-drive attempting to engage. I have to jump on the highway in a few days to drive a few hundred miles and I really don’t have time to do an in depth fix, so does anyone know if I could I possibly disconnect and cap the vacuum line that’s responsible for activating four-wheel-drive and just disengage it entirely for now? Would I still be able to drive normally?

Year, make and model?

If you have the feature - shift your drive mode selector to 4A, which will enable the vehicle to be driven at any speed and on any type of road. The vehicle could be driven safely until you can diagnose and repair. This permits full-time engagement of the front IWE hubs.

Most likely you have a vacuum leak at one of the hard IWE plastic vacuum line fittings, or where they attach to the front IWE hubs.

 

[eddytheexpy]

Sounds like a IWE vacuum leak (super common).

If you’re in a pinch, 4a will get you by for the time being without any damage. This works because the vacuum is dropped engaging your front hubs to the front axle but the transfer case will only engage output power if it senses your tires slipping. Effectively doing the same thing as pulling the vacuum hose but won’t freak out your rig or pull debris into the vacuum lines from it being open.

Here’s a thread where I go into detail on the problem (post #2) and give a link to the vacuum hose I used. Super easy fix to replace the hose if you’ve narrowed it down to that which is usually the culprit in help I’ve given on the topic. Just need needle nose pliers, a screw driver and a basic ratchet set.

 

[vanessa june]

Sounds like a IWE vacuum leak (super common).

If you’re in a pinch, 4a will get you by for the time being without any damage. This works because the vacuum is dropped engaging your front hubs to the front axle but the transfer case will only engage output power if it senses your tires slipping. Effectively doing the same thing as pulling the vacuum hose but won’t freak out your rig or pull debris into the vacuum lines from it being open.

Here’s a thread where I go into detail on the problem (post #2) and give a link to the vacuum hose I used. Super easy fix to replace the hose if you’ve narrowed it down to that which is usually the culprit in help I’ve given on the topic. Just need needle nose pliers, a screw driver and a basic ratchet set.

great info that’s exactly what i thought it might be. However in this case i’ve heard that running it in 4A might overheat the transfer case with driving long road distances is this true?

 

[eddytheexpy]

great info that’s exactly what i thought it might be. However in this case i’ve heard that running it in 4A might overheat the transfer case with driving long road distances is this true?

So in 4A the IWEs are dropped engaging the front axle, the transmission is geared to supply power to the front axle BUT the clutch in the transfer case isn’t engaged. So sure, you’re putting wear on the chain connecting the transmission to Tcase and front drive components but those are designed for this purpose. The Tcase isn’t doing a damn thing until it senses your tires slipping. So (IMHO) long as your Tcase and front differential are in good maintenance I’d say you’re actually doing your vehicle a favor if you don’t usually engage it regularly. This will get components moving and covered in their respective lubricants which is good for the system. Just get around to fixing the vacuum leak in the near future.

In the time being, you might see a slight drop in fuel economy because your rear axle is pushing the vehicle which is forcing the front drive train to move. Aside from that, I say send it!

Btw, front diff and Tcase in good maintenance means new fluids within the last ~75k miles and no leaks.

If you’re scared about leaks, any 1/4” rachet can take off both fill plugs. Stick your finger in and your finger should immediately touch fluid below the lowest edge of the plug you pulled.

 

[99WhiteC5Coupe]

great info that’s exactly what i thought it might be. However in this case i’ve heard that running it in 4A might overheat the transfer case with driving long road distances is this true?

Your vehicle owner’s manual (also available on line to read) will have specific information regarding driving in the various drivetrain modes.

 

[Gumbyalso]

I recommend you look at TSB 22-2219 that removes a couple vacuum hoses and caps them. It cured the IWE grinding issues on my 2011. I wasted time and money chasing the issue myself. I had it at the dealer for rocker arms and lifters and had them listen to the grinding while it was there. They complied with the TSB and the problem disappeared.

 

[99WhiteC5Coupe]

I recommend you look at TSB 22-2219 that removes a couple vacuum hoses and caps them. It cured the IWE grinding issues on my 2011. I wasted time and money chasing the issue myself. I had it at the dealer for rocker arms and lifters and had them listen to the grinding while it was there. They complied with the TSB and the problem disappeared.

That Ford TSB eliminates the 2WD (RWD) feature (that the vehicle was designed and built with) and keeps the drivetrain in AWD.

Driving in AWD always can lower fuel mileage and increase drivetrain wear.

The system is not hard to troubleshoot and repair. Usually the issue is a vacuum leak at one of the connectors, or a damaged plastic vacuum line.

 

[Gumbyalso]

That Ford TSB eliminates the 2WD (RWD) feature (that the vehicle was designed and built with) and keeps the drivetrain in AWD.

Driving in AWD always can lower fuel mileage and increase drivetrain wear.

The system is not hard to troubleshoot and repair. Usually the issue is a vacuum leak at one of the connectors, or a damaged plastic vacuum line.

I assume you haven't incorporated TSB 22-2219 on your Expedition. I can definitely state that the 2WD feature was not eliminated with compliance with TSB 22-2219. The switchable modes for a 2011 are 2H (4x2), 4A (4x4 Auto), 4H (4x4), and 4L (4x4 Low). I still have all four of those modes. It's very noticeable when a 2011 is in 4WD and mine is definitely not unless I select 4H. The only thing that TSB does is delay the operation of the solenoid for a half mile. You still must shift the TC into 4H/4A/4L to be in 4X4. The information that TSB 22-2219 puts your Expedition into full-time 4WD is incorrect. I did not have a vacuum leak, damaged lines, or damaged connectors. I know because I personally vacuum tested the system and unnecessarily replaced a few parts. Instead, I had a poorly designed system that was corrected with 22-2219. I think the bad gouge floating around that 22-2219 puts you in All Wheel Drive or full-time 4x4 is preventing owners from getting the correct fix.