Dylan Nettenstrom

First off I have a 2006 F150 FX4 5.4L SCAB 4WD and started noticing something funky with my 4WD.

I was on backroads a couple weeks ago and tried switching into 4Hi (~35mph) and got a nice "ice in blender" sound coming from the front halfshaft/hubs. The 4WD would not engage until I came to a complete stop. I shifted back to 2WD fine and decided to try switching to 4Hi at a lower speed. My truck would not engage 4Hi even while rolling at idle speed, only at a stop. Everything else works fine.

I have only owned this truck for approx 8 months, so I dont know if this is normal or not. I thought I used the 4WD a couple times while shifting on the fly with no issues (maybe I didnt notice the problem). Even my 2002 Ranger was able to shift to 4Hi on the fly at a reasonable speed.

I found the 2006 F150 Owner manual and this is what it said:

"Shifting between 2H (2WD high) and 4H (4WD high)
• Move the transfer case lever between 2H (2WD High) and 4H (4WD
High) at a stop or any forward speed up to 55 mph (88 km/h).
Note: Do not perform this operation at speeds above 45 mph (72 km/h)
if the outside temperature is below 32°F (0°C).
Note: Do not perform this operation if the rear wheels are slipping.
Note: Some noise may be heard as the system shifts or engages; this is
normal."

I did some research on here and read most of the threads about how the 4WD on this truck works and found out about the common IWE solenoid issue.

I replaced the IWE 4WD vacuum solenoid with the new version which did not solve the problem.

I believe I narrowed down the problem to either faulty IWEs and/or bad shift motor on the tcase. I wouldn't mind doing the work, but since I have an extended warranty, I decided to take my truck to a shop and have somebody else do the work.

The first shop pulled these two codes (no CEL):
P1824: 4WD Electric clutch relay circuit fault
P1827 4WD low clutch relay ground short

Their solution was to replace the entire tcase or have it rebuilt at the transmission shop. They had no more thoughts on why everything worked properly except for the ESOF speed.

I didnt feel this was right so I decided to take my truck to a different shop to get a second opinion.

Same thing... they wanted to replace/rebuild the tcase, new shift motor and replace the hub assemblies (not IWEs). They contacted my extended warranty company and they approved the service and agreed to pay for it.

I let them do all that work and all I had to pay was $100 deductible instead of $2100.

Verdict: After all that work, I still cant shift into 4Hi over 15mph without grinding...

The mechanic told me the hubs will always grind if vehicle is put into 4WD at high speeds, and just recommended to engage less than 10mph and I'll be good. He told me my truck does not have the system to synchronize the hubs and halfshaft while at speed...?

I feel like this is a load of .

Referencing this forum : https://www.f150forum.com/f72/how-di...m-esof-186872/
It sounds like the electromagnetic clutch inside my tcase is not working properly (which is why I had the codes), which in turn means my halfshaft arent syncing up to my hubs... that and my IWEs could be worn down now... and/or I have a slight vacuum leak.

What are your guys' thoughts?

Thanks in advance.

Ford123

I don't think you're in the wrong here. If I'm not mistaken all of these trucks are shift on the fly up to a speed of 55mph like you've stated. I've never had a problem shifting on the fly, I've shifted doing 80kmh or about 50mph with no grinding. As for your issue with the grinding I had a similar issue where my truck would randomly half engage the 4x4 causing a grinding, I had to slow down to about 10 mph and then it would disengage. Brought it to a mechanic, he changed the front diff fluid and it never happened again.

lewissa81

A vacuum leak would cause the iwe's to try to engage WITHOUT switching into 4wd. The iwe's need vacuum to disengage, not engage, so I don't see that being the cause.
There is a spring inside the iwe actuators. It may be binding, causing more resistance when trying to engage. You may not notice it when you're at a stop because it has a little extra time to get the teeth fully seated.
Basically, I agree that the iwe actuators are bad, or going bad.

homer

Exactly like Lweissa wrote.


It sounds like it's not releasing the vacuum properly, the springs in the IWE can't push the hub in (although I'm doubting this), or the teeth are worn that they're not meshing nicely. In 2WD mode, the solenoid allows vacuum through... basically when the truck is off and there's no vacuum, the hubs engage (on F150's, not the same on all F250/F350's with auto hubs) as the vacuum is cut and the IWE springs push the hubs to the engage position. This is actually handy if you shift the transfer case into 4x4 and park on a hill with snow whereas your rear only engaged could cause the vehicle to slide down (I've seen this in our old driveway haha). When you start the truck in 2WD mode, the vacuum is allowed to flow through the solenoid disengaging the hubs. When you shift to 4x4, it cuts the vacuum to the IWE hubs to allow the hubs to re-engage but if the vacuum cannot release at the hubs then it's like holding a straw the hubs will slowly start to re-engage causing the grinding noise (which I believe goes through the return line - there's 2 lines at the IWE joined together) if it's partially plugged. The hubs (or one hub) is/aren't releasing properly either due to teeth, bad springs, or vacuum not releasing properly/fully is my guess. I *think* there might be a check valve in there somewhere too, it's been a while since I've dug into mine.

This sounds entirely like the Integrated Wheel Ends (IWE) and not the transfer case at all! As well, I've NEVER had a grinding noise shifting in or out of 4WD with my 2005 F150 (5.4) at speed. The only time I ever had the grinding noise was when my IWE failed not being able to hold vacuum (very common issue). This doesn't sound the case with yours... With the IWE seal failing, usually the one or both of the IWE hubs start to engage while driving in 2WD, yours sounds like it's SLOWLY releasing when shifting into 4WD. This is why I'm convinced it's vacuum related, spring (although I'm doubting that), or worn teeth.

I have shifted at 80km/h with no issues in the past although I don't *like* to do it haha. There's no reason you shouldn't be able to though.

There's tons of documentation on here as well of course. I've posted a document back in 2009 but (I keep forgetting who!) someone recently made a very detailed one and he usually chimes in on this. Maybe this will help (picture attached).


Additionally, if you pull the line off of the IWE solenoid, you essentially force the hubs to lock. The transfer case will still shift in and out of 2WD/4WD so you can always try that and if you don't hear the noise you know that's it. The downfall is you're spinning your front end wearing parts and burning a few more MPG but for test purposes it'd be fine and may somewhat help determine more of the cause (although it won't tell you really if the teeth are worn or spring is worn). I did it for a period of time when my solenoid was shot (I needed 4WD!) as my hubs wouldn't lock (but T-Case would shift).


Hopefully this helps and doesn't add confusion.

Dylan Nettenstrom

Thanks to all the responses. It sounds like IWEs are the culprit, as suspected from the beginning. Its a tricky diagnosis because I cant find anybody else in the forums or TSBs with these symptoms.

But now I can officially rule out hubs, tcase, and shift motor... Glad I didnt have to pay for all that mumbo jumbo though

I just have to convince the shop (and warranty company) that all that work didnt fix my problem. Still shocked the mechanic said I cant switch on the fly above 10mph, when the owners manual specifically says 55mph.

techrep

iTrader: (1)

I really don’t know how changing the front diff fluid has anything to do with your IWE...

Ford123

Neither do I, unless he did something else he didn't tell me about.

Dylan Nettenstrom

I had the shop replace the IWEs and that solved my initial SOTF grinding problem.

Now I have some weird whine noise that can primarily be heard intermittently while driving at slow speeds. The whine responds to small changes when depressing the throttle. It is almost like I have to be going the right speed to get it to happen. I cannot get the truck to make the sound while parked. I dont know how it is related to the IWE, hub assembly replacement or transfercase work, but I didnt have it before I went to the shop. Maybe the mechanic didnt install something right?

Sounds like the start of another wild goose chase

techrep

iTrader: (1)

May be an Idler or tensioner pulley going bad...

Dylan Nettenstrom

I dont think it is related to the engine. The noise is not responsive to RPMs, only to vehicle speed.

I only get this squeal/whine when the truck is moving at slow speeds up to 30mph. I cannot replicate the sound while in park or revving the engine. The noise does not happen right away on a cold truck. I can only get it to happen after driving on the freeway for a couple miles after the truck is warm.

Braking does not effect the sound, neither does shifting to N or 4WD.

I've read a bunch of old threads and most end with no results. Most people have pointed towards hubs/wheel bearings, pulleys, ball joints or u-joints.

Sort of ruled out ball joints because speed bumps and turning does not make a difference.

I had the IWEs and hub assemblies replaced last week. And the u-joint symptoms seem to be very different. I dont know what else it could be.

Should I just take it back to the shop that did all the previous 4x4 work? I didnt have this noise before the IWEs and hubs were replaced. All of the previous work was covered by the extended warranty, but I've already been in there 3 times and they dont seem very knowledgeable about F150s.