4x4 Issues
#16
07-15-2015, 11:42 PM
BlackThunder12,
What you experienced was - unfortunately - fairly normal for the current 4WD engagement system on F-150's The system relies on two IWEs (think of these as a form of automatic locking hubs), one at each wheel hub that lock and unlock the actual wheels to the front half shafts. The IWE's are controlled by vacuum from a solenoid. Oddly enough, applying vacuum actually disengages the IWEs.
The most common problems with this system are the Solenoid that applies vacuum to the IWEs going bad and not fully engaging (or disengaging) the IWEs. This grinds them up in pretty short order. (This was probably the noise you heard.) If the Solenoid fails completely, you just can't lock the IWEs.
Second, the vacuum lines that go from the Solenoid to several Check Valves and then to the IWEs can crack and / or otherwise leak. When this happens, you're right back into the partially engaged or disengaged issue from above.
Finally, the electric motor that engages or disengaged the Transfer Case has a nasty habit of going bad - when you need it most. This ESOF motor is the thing that really needs the most exercise and sometimes just tapping it with a hammer will wake it up. If it doesn't wake up and move though, it doesn't matter if your IWE's are locked or not, you have no power going to the front axle.
Believe it or not, the system isn't terribly bad, but it has several known issues. I can't believe your dealer didn't know about them. Just do a little searching here on IWEs and you'll finds tons of stuff on the issues.
Hope that helps.
Tom
What you experienced was - unfortunately - fairly normal for the current 4WD engagement system on F-150's The system relies on two IWEs (think of these as a form of automatic locking hubs), one at each wheel hub that lock and unlock the actual wheels to the front half shafts. The IWE's are controlled by vacuum from a solenoid. Oddly enough, applying vacuum actually disengages the IWEs.
The most common problems with this system are the Solenoid that applies vacuum to the IWEs going bad and not fully engaging (or disengaging) the IWEs. This grinds them up in pretty short order. (This was probably the noise you heard.) If the Solenoid fails completely, you just can't lock the IWEs.
Second, the vacuum lines that go from the Solenoid to several Check Valves and then to the IWEs can crack and / or otherwise leak. When this happens, you're right back into the partially engaged or disengaged issue from above.
Finally, the electric motor that engages or disengaged the Transfer Case has a nasty habit of going bad - when you need it most. This ESOF motor is the thing that really needs the most exercise and sometimes just tapping it with a hammer will wake it up. If it doesn't wake up and move though, it doesn't matter if your IWE's are locked or not, you have no power going to the front axle.
Believe it or not, the system isn't terribly bad, but it has several known issues. I can't believe your dealer didn't know about them. Just do a little searching here on IWEs and you'll finds tons of stuff on the issues.
Hope that helps.
Tom
Hi!
Where are located the solenoids, electric motors and the stuff related? My truck does't engage 4X4.
Thanks!
Art
#17
08-18-2015, 12:01 AM
Hello all and thank you for all the posts regarding the F150 IWE system it has taught me a lot. I am a new member and have owned a 2009 5.4 L f150 for a number of years now and have recently begun to experience the typical metal on metal grind from the front end under low speed acceleration. I had the problem diagnosed by a local shop as failure of the accurators and as of today had them replaced. The problem itself is improved but does still occur despite this costly repair. Under 4WD the sound currently disappears and believe the problem to possibly be the check valves or solenoid. Was hoping somebody might have some imput. Im no mechanic by any means but have located the solenoid and will be replacing it soon but am not sure of the check valve locations on the 2009. Thanks to all who have posted on this topic.