Ok. So I figured out what is causing the low growl when slowing down in my truck. It seems to have something to do with the 4WD system. If I engage the 4WD while I hear the growl, it goes away. It is also not present when testing the vehicle while in 4WD. I recently had the common IWE solenoid issue where I was getting noise sometimes from what seem like my front drivers side wheel then I would here a clunk and it would go away. My mechanic cleaned/dried out my IWE solenoid which has stopped that from reoccurring, but I still have the growl.

Would the growl be from insufficient vacuum to the actuators on the hubs only partially engaging the 2WD? Or damaged actuator gears from when I was having the engage/disengage issue due to the solenoid? How damaging is it to drive it n this state? The growl is worse sometimes than others...

If any of this is inaccurate sounding please forgive me. All I know about this stuff is the little understanding I've gotten from reading this forum...

Steve

 

I believe you have correctly diagnosed your situation (speaking from the experience of the exact same problem and resolution).

It is very damaging to the IWE(s). They are a softer metal than the axle and are being worn away by the axle teeth. It's been a while since I had mine all apart, but I believe these shavings could conceivably make their way to the wheel bearing and damage it too.

 

So would replacing the solenoid resolve the issue of vacuum? or do I need to replace the actuators as well at this point?

 

Like I said in your other thread...it is my belief that once the IWE start grinding, there is damage done which can cause the entire mechanism to gum up and continue to deteriorate. Replacing the solenoid alone MAY fix this, but it might not. If you have already replaced the solenoid (and hoses?) and it is still making noise, then you should probably replace the IWE(s) also.

 

It may resolve your issue - only if the solenoid was faulty. If you were loosing vacuum due to a leaking vacuum line or bad check valve, replacing the solenoid will not do much of anything. And - as I've stated time and time again on this type of thread - if you have any of the problems stated above and your IWE's grind for any length of time, they're toast and need to be replaced. The grinding noise you hear is metal on metal between the axle shaft and the IWE - destroying the IWE.

 

Soonest I can get it in to my guy is Thursday the 14th... He is going to do what was suggested by the TSB:
===================================
FORD: 2004-2006 F-150
LINCOLN : 2006 Mark LT


ISSUE:
Some 2004-2006 F-150 and 2006 Mark LT 4X4 vehicles built before 4/24/2006 may exhibit a noise in 2 wheel drive from the front Integrated Wheel Ends (IWE) and/or the 4X4 system being inoperative. The IWE solenoid may have ingested water and passed it to the IWE system causing water contamination in the vacuum portion of the system. A shorted IWE solenoid can set the codes C1979 and C1980. If either code is present, the 4WDH light will be inoperative.

ACTION:
Use the following Service Procedure to check and repair the 4X4 system.

SERVICE PROCEDURE

Replace the IWE solenoid. Torque the new design bracket and solenoid to 62 lb-in (7 N-m). It will be necessary to remove the vacuum lines from each IWE down at the wheels to check for water being present.
If no water is present at the vacuum line at the IWE, install the new solenoid with bracket. Reconnect all vacuum hoses.
If water is present allow it to drain from the vacuum lines. Then follow the updated procedure outlined in 2006 Workshop Manual (WSM) on-line version, Section 308-07A, Pin Point Tests B21 and B22. These tests checks IWE leak rates with vacuum and will remove any residual water from the IWE. Reconnect all vacuum hoses.
If the IWE looses vacuum quicker than specification. Refer to WSM, Section 204-01B for normal diagnostic procedures.

PART NUMBER PART NAME
6L3Z-9E441-A (CX-2117) IWE Solenoid
===============================================

What I am hearing is more of a low growl sound - similar to new tire treads on pavement - but deeper sounding and more noticeable the slower i get... Would this be the metal on metal you are referring to or would that sound different?

 

Yes, yes, yes and yes.

It's pretty much a guarantee that your IWE's have damage.

 

Would it be at all beneficial to try and drive in 4WD as much as possible until I can get it into the shop? Would this minimize the damage? I know ideally would be to not drive it at all but...

 

Been there, done that, not a good idea. On dry pavement four wheel drive is not good on the mechanics of your drive line (A LOT more expensive than the IWE) and tires. I tried removing the vacuum line so that the IWE were engaged but not the transfer case. Turns out there is a clutch in the transfer case too and that started to heat up and I could smell it even though the transfer case was not engaged.

Your IWE are already damaged and they are the weak spot in the system, so I would just leave it as is in plan on replacing them ASAP

 

Assuming these will get worse over time - and I cannot get to the shop for another week and need to drive some, will the system eventually fail completely and then what? Permanent 4WD? No vacuum to keep it in 2WD?

Grinding/growl is getting worse/more noticeable... I flip it into 4WD(noise goes away) and then back to 2WD and that seems to make it worse. Is that because I am having to then build back vacuum from the engine for the 2WD???????????

 

My problem stems from a bad vacuum line. I bandaided it for now. must fix soon. Damage is done, parts are worn out. Another week wont do much more damage than is already done.

Fingers crossed.

 

Ok, exactly what I thought it was. Turns out the front left Actuator was shot... seal was ruined and there was water, dirt and rust inside. Was holding no vacuum. Had my mechanic replace the Solenoid and both Actuators - even though the right one was fine. Performed Solenoid TSB, tested vacuum readings, etc.

Had my mechanic inspect the Hub gears as well and he said they were fine. I think Dealerships like to replace both because it means more $$$ in their pocket.

No more growl... Ahhhhhh

Thanks for everyone's input.
Steve