The Ford F150 4X4 4WD uses an IWE (Integrated Wheel End) for a four-wheel drive to run on low traction surfaces like snow and mud or off-roading.
IWE typically consists of a wheel hub assembly, a front-drive axle with gear teeth, a locking hub actuator, and a vacuum solenoid valve with vacuum hoses attached.
But people often face vehicle-related issues linked to the IWE system since the vacuum-operated system fails and leaks over a while and look for a 4X4 actuator bypass to fix the issue.
If you are looking for a Ford F150 4X4 actuator bypass, then options could be disconnecting vacuum solenoid hoses, unplugging the vacuum hoses on the actuator, or installing free wheel hubs which have vacuum actuator delete.
Alternatively, you can replace the malfunctioning vacuum solenoid valve, fix the vacuum leak in the IWE system, or replace the faulty IWE actuator after a thorough inspection instead of bypassing Ford F150 4X4 actuator.
Are you facing issues related to the 4WD IWE system and looking for Ford F150 4X4 actuator bypass options to fix vehicle noise or 4WD engagement issues? Then you are at the right place. Stay tuned to get all your queries answered!
Table Of Contents
How Does Ford F150 4X4 Actuator Work?
In the case of the ford F150 with the 4WD, when the vehicle and engine are running and the selector switch or floor shifter is in 2H mode, the vacuum pressure will be applied to the hub actuator that would pull the gears out of engagement with the drive axle gears and the hub actuator is moved out of gear, thus disengaging the 4X4.
But when you select the 4H mode, the vacuum pressure from the engine via. the vacuum solenoid to the hub actuator is released.
That would cause the diaphragm of the hub actuator to move the hub gear to engage and lock with the drive shaft end gear thereby engaging the 4WD.
There is a vacuum reserve box that is located between two check valves which are connected by a vacuum hose. The vacuum line starts from the intake system via. the first check valve is connected to the vacuum reserve box.
A T joint connects the first check valve to both the vacuum reserve box and the second check valve. These check valves and vacuum reserve box help in applying and releasing vacuum irrespective of varying engine vacuum so that whenever a particular mode is selected, the vacuum pressure applied to the IWE will be immediate.
The vacuum solenoid valve is controlled by vehicle ECU which senses the drive mode switch position (4H or 2H) and directs the solenoid by controlling the 12V signal to either permit the vacuum pressure in 2H mode or blocks it in 4H mode from the engine to the hub actuator.
Ford F150 4×4 Actuator Bypass Options?
People often look for ford F150 4X4 actuator bypass to fix issues related to grinding noise when accelerating, front end noise when turning, or when 4WD is not getting engaged in 4H mode.
To bypass the Ford F150 4X4 actuator, you have the following options
Disconnect vacuum solenoid hoses
The vacuum solenoid valve is typically located under the engine hood near the firewall. To bypass the Ford F150 4X4 actuator you simply need to disconnect the vacuum hoses that are connecting the vacuum solenoid valve to both the IWE side and the engine intake side.
Out of these two, the hose which is connected to the intake side that has the check valve is essential to be disconnected since it is the one which supplies vacuum to the solenoid.
By removing the vacuum hoses you will be releasing the vacuum applied to the IWE and hence the hub wear will be engaged with the drive axle gears. So four-wheel drive will be locked thereby bypassing the ford F150 4X4 actuator.
Ensure that you plug the open free end of the vacuum hoses and vacuum solenoid after disconnecting the hoses with plugs or bolts to prevent foreign matter accumulation the system.
Even when you select the 2H mode with the dash selector switch or shifter lever, no vacuum will be applied to the hub actuators and thus the gear disengagement will not commence.
The vehicle will always run in 4WD and that would lead to comparatively lesser fuel mileage since there will be an additional load on the engine due to the continuous operation in 4WD.
Unplug the actuator vacuum hoses
Instead of disconnecting the vacuum hoses on the vacuum solenoid valve, you may alternately unplug the vacuum hoses connected to the IWE hub actuator for Ford F150 4X4 actuator bypass.
Two nozzles are present on the IWE hub actuator. The larger one is connected to the vacuum solenoid valve and the smaller one is just a vent.
Unplugging the vacuum hose that is connected to the larger nozzle that gets vacuum supply from the vacuum reserve box is essential to bypass the ford F150 4X4 actuator.
This will prevent vacuum pressure from getting applied to the IWE hub actuator thus the vehicle gears would always be in locked condition for 4WD.
After unplugging the hoses, remember to close the open nozzle ends with some plugs. Otherwise, the moisture, water, and dirt would find their way into the system and would damage the IWE parts and would face issues when you reinstate the vacuum hose connections when you permanently want to fix the IWE problems.
Install vacuum actuator delete
Ford makes use of the IWE hub actuator to lock front axles to the wheel hubs while in 4WD and allows the wheel hub to rotate freely from the drive axle in 2H mode.
But this setup works till the rubber diaphragm is intact in the hub actuator after which leads to vacuum leak and grinding noise problems.
Apart from unplugging the IWE vacuum hoses, you may try installing free wheel hubs to bypass the 4X4 actuator in your ford F150 that would permanently engage the wheel hub to the front axle gears and would keep the vehicle in 4WD all the time.
Some aftermarket designs of the free-wheel hubs have dummy vacuum posts where you can connect the vacuum hoses that in turn are connected to the vacuum solenoid valve.
This helps in reinstating the system to its original condition when you want to install a regular ford F150 4X4 hub actuator to have both 4H and 2H modes in your vehicle to prevent the fuel efficiency penalty caused by the vacuum actuator deletion.
Alternative To Ford F150 4X4 Actuator bypass?
Before you think of bypassing the Ford F150 4X4 actuator, you can explore troubleshooting the malfunctioning IWE system parts to fix the vehicle-related problems like grinding noise and 4WD not engaging, etc. once and for all.
Below are the probable permanent solutions that can be tried before bypassing Ford F150 4X4 actuator.
Malfunctioning vacuum Solenoid
The vacuum solenoid is the part that needs to be blamed for many vehicles related problems. The earlier vacuum solenoid goes bad when the rainwater enters the solenoid valve in the absence of any rain hood kind of design over the vacuum solenoid.
Later models are provided with a rain hood cover over the vacuum solenoid to prevent rainwater entry.
A malfunctioning vacuum solenoid would not either release or apply the vacuum pressure to the hub actuators, hence in 4Wd, there would be either continuous engagement or no engagement irrespective of the drive mode selected.
Also in case of a bad vacuum solenoid, less vacuum will be applied to the hub actuator in 2H mode and this causes partial disengagement of the hub end gear with the drive shaft gears instead of complete disengagement that happens when the vacuum is completely applied.
This partial disengagement in 2H mode causes the gears to make a grinding noise when running.
You do not need a vacuum gauge or voltmeter to check whether the vacuum solenoid is functioning properly or not. Connect the vacuum solenoid to the electrical connector.
Simply disconnect the outlet vacuum hose from the outlet nozzle going towards the IWE, keep the inlet vacuum hose connected to the engine intake, and check the valves.
Put the vehicle in 2WD and you shall be able to feel the vacuum at the outlet nozzle then put the vehicle drive in 4WD mode, and there shall be no vacuum at the outlet nozzle.
This confirms that the vacuum solenoid is functioning normally. If not, the bad vacuum solenoid to be replaced with a fresh one.
Vacuum leak
If there are leaky vacuum hoses or any other component in the IWE system starting from the intake system to the vacuum solenoid valve and then to the IWE hub actuator. then also it will have a similar effect as a faulty solenoid valve.
The leaky vacuum hoses would apply less pressure to the hub actuator and that would cause partial disengagement of the hub gears with the drive axle gears which otherwise have to completely disengage.
This partial disengagement of hub gears starts creating undesirable grinding noise in 2H mode.
The vehicle issue would be more noticeable when accelerating on an uphill gradient since in that case, the vacuum leak in the system could not be compensated by the engine vacuum due to wide open throttle plates.
You need to thoroughly inspect the vacuum hoses and IWE parts for a vacuum leak and seal it to get rid of the vehicle noise.
You may check the vacuum with a vacuum gauge. If a 5 lb vacuum is available at the actuator or vacuum solenoid then the hub gears will disengage/unlock the actuator, the vacuum shall hold but a vacuum loss of 1 lb over 1 minute can be acceptable.
You need to check the vacuum levels between various parts to pinpoint the issue area. If the vacuum is not getting hold between the 4X4 hub actuator and vacuum solenoid actuator then there could be blown-out seals or diaphragm at the actuator end apart from leaky vacuum hoses.
Depending upon the location where the vacuum is not getting hold, the leak could be at the vacuum reserve box, check valves and the engine vacuum source point.
Faulty IWE actuator
The vacuum solenoid is the part that frequently goes bad since there are chances of water entering it unless you have a hood cover type design of vacuum solenoid.
Once the water enters the solenoid and goes bad, the water finds its way into the hub actuator and it could damage or crack the rubber diaphragm causing a vacuum leak.
If the 4X4 hub actuators have failed in the engaged position and still your 4WD doesn’t work, then the problem isn’t related to the IWE and the issue is something else.
You can check by jacking up the vehicle and in the engine switched off condition, if the wheels spin freely with respect to the drive axle then it is failed in the disengaged position. But if it spins along with the axle then it is failed in the engaged position.
When the engine is running and the drive mode is in 4H, you shall not be able to move the drive axle with ease simply by rotating the wheel, otherwise, there is a problem with the IWE on that side.
It is worthwhile to note that disconnecting the vacuum hoses will not work if the actuators have failed in the disengaged position. The 4WD is possible if the actuators have failed in the engaged position.
You may need to check the IWE actuator and replace it with a new one if required after a thorough inspection.
Conclusion
The IWE system is quite simple if you understand the part’s function and how to troubleshoot.
Once you know the root cause, the countermeasure would be simple and it is reliable. If you are not a DIY kind of guy, then you may show the vehicle to a qualified professional to fix things for you.
Bypassing the ford F150 4X4 actuator would affect the fuel mileage since the hub actuators will be continuously engaged with the drive axle shafts and add on to the load on the transmission.
Hence it is recommended to carefully analyse the IWE system parts one after another to permanently solve the problem instead of simply bypassing the ford F150 4X4 actuator which could be a temporary solution but would not solve the problem completely.
Happy Motoring!
References
https://www.f150forum.com/f4/bypassing-vacuum-fwd-control-316613/
https://www.ford-trucks.com/forums/716167-bypassing-iwe.html
https://www.f150online.com/forums/2009-2014-f-150/512909-bypass-iwe-question-temporary-fix.html
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