I have a grinding/scraping sound when driving in 2WD. Last weekend my mechanic and I looked it over and determined that I should replace the IWE Solenoid. I ordered a new IWE Solenoid (the new one with the water hood) and in the meantime he put a jumper on the vacuum line where the IWE Solenoid goes to jumper the two vacuum lines together. I drove home and the sound came back. I then later discovered that if I flip the 4WD switch into 4H (without actually activating the 4WD because the solenoid is bypassed) the sound goes away completely. I drove to and from work with it like that for 2 days and didn’t have any noise at all.

The new IWE Solenoid came in last night and I installed it. The sound came right back with the truck in 2WD again. When I flip it into 4H the sound goes away and the 4WD does actually work, I can feel the tires gripping the road. Then I flip it back into 2WD and the sound comes back.

So right now I am bypassing the new IWE Solenoid (with the vacuum jumper my mechanic originally installed) and driving with it in 4H.

Anyone know what the problem might be or where to go from here?

 

If not the solenoid, it is either the vacuum lines to the IWE's, or a bad IWE itself.

 

So we should check the vacuum pressure at the wheels next. If that checks out ok, then it's probably a bad IWE?

 

Correct. Make sure the vacuum lines are not split or cracked.

 

Would it be the IWE or the hub assembly? I ran across this thread in my searching: http://www.garagejournal.com/forum/s...ad.php?t=24238

 

They are one and the same. IWE is the hub assembly. All one part.

 

So the IWE/Hub assembly is This and the IWE Actuator is This and it's the hub assembly that needs to be replaced. Correct?

 

Can't say for sure, but the IWE is one piece. There is no separate bearing, etc. Look the parts up at TASCA to get an idea. www.tascaparts.com

 

That didn't really help much. I did find the front hub assembly there and looked at the exploded diagrams. They don't really break down the different models of the hubs on that site or anything. In doing the research I've done I now know there are two different models of hubs on the '04 F150; pre and post 11-28-2004 have different hubs and they don't mention anything about that on the Tasca site. The diagrams there also had 8 lugs, not 6.

 

Its most likely a bad Vacuum Line, I just had the same exact issue. My line was cracked and then it ended up disconecting all together. Check your lines. I could actually hear mine sucking up air at the leak with my head in the wheel well.

 

I am pretty sure he checked the vacuum line. I'll look it over again though. Could a bad vacuum line cause the problem on only one side? It's only the driver's side that has the problem.

 

i just had the same problem- was on vaca for a week and when i got back i heard a grinding noise - took it to dealer since i had power train warrenty and they had found that a vacuum line was chewed up by some critter

recheck all vacuum lines

 

Read/look at pictures on these two threads. One is a trouble shooting guide and the other is on replacing the IWEs on the wheel hubs...

http://www.ford-trucks.com/forums/83...then-some.html

https://www.f150online.com/forums/20...replacing.html

I replaced both IWEs and the solenoid to get my system working quietly again. Not hard to do. IWEs can be purchased online for about $75-$80 each. If you tell your local dealer about that, they might match the online price.

 

You will find that once an IWE starts grinding - no matter what caused it - you will pretty much have to replace the IWE because it gets too messed up to work properly. Of course this also says that you have to fix what caused it to start grinding in the first place - which is usually a bad solenoid or a leaking vacuum line.

 

^ ...what he said!