Dusterdude72

ok, so let me start by saying that I recently replaced my IWE solenoid . ( my 4x4 sometimes would not engage in really cold weather ....a couple times of which it ATTEMPTED to engage and you could hear the cv splines grind against the IWE on the drivers side)...all the lines were blew out and hubs also and new solenoid installed and 4x4 has worked just fine since. Have not noticed any out of the norm noises or anything. (not even sure if the issue I am about to mention is related but figured I would mention it anyhow).

Anyways, I parked the truck for about 4 days. Today I got in the truck and I noticed that in 2 wheel drive at around 35 mph I start to hear a "hum" almost like the sound you would hear with an aggressive tire... This "humming" noise increases the faster I drive (it sounds like its at the front of the truck and MAYBE more so on the drivers side). There does not seem to be any vibrations in the steering wheel or lack in quality of steering,the sound does not appear to change on turns or when I shimmy the wheel back and forth driving down the road........just this noise).

NOW.....if I put it in 4x4....the humming noise goes away. everything sounds as normal. So I can guarantee it is not a tire noise, I highly doubt its wheel bearing noise. I am stumped on what the noise might be since everything was fine and then I parked the truck for a few days and all of a sudden this noise came about. Not like I was out hot ******* the truck or jumping ditches and exploded something in my diff or t-case or something.

Anyone had a similar issue with these trucks and/or know what the issue might me?

Dusterdude72

P.S. for what it counts, my truck is in alignment and I can confirm that in 2 wheel drive I slide all over the snow and in 4 wheel drive I get traction. so all of that is working.

Dusterdude72

I did a bunch of searching and was able to find one thread that sounds like it is a similar issue to mine.

Guy mentioned same issue as me (same sound under the same conditions and in the same range selection). And he made mention that one of his IWE's was at fault and basically was locking 1 front wheel in at all times . So the humming noise could be caused by the limited slip spooling up the spider gears in the front diff maybe?.

I don't think any damage has been caused because locked into 4 wheel drive everything sounds fine. So whatever it is, I think I caught it early enough.

As of right now I am leaning toward a bad IWE or MAYBE a bad CV shaft. But anyone else who is more familiar with similar issues on these trucks is welcome to chime in.

EBC-150

Your 4WD drive may be working properly, but have you checked the 3 check valves in the vacuum system? These valves in conjuction with the vacuum tank, keep a supply of vacuum to the IWE's during low vacuum engine conditions (such as when 'lugging' or accelerating). If the checks are bad, the surplus vacuum will be depleted and the IWE's can start to engage- making all kinds of 'good' noises.

Dusterdude72

I thought there was only 2? and yes I had already checked them back when I was troubleshooting the previous 4 wheel drive issue that ended up being the solenoid that I then replaced.

BCURRY06F150

I have a very similar problem happening right now it started last Friday all of a sudden the 4 wheel drive and 2 wheel drive work properly and both IWEs as well as the vacuum solenoid were replaced about a year and a half ago because the hubs were loosing vacuum every time I parked. Now there is a roaring/ humming sound from 0 mph to about 40 and then it fades away the faster I go and it sounds like it is around the front drivers side a well so it has to be something that yours is doing as well?

MONSTERTRUCK 150

My 13 SCREW was doing that and my hub actuator was cracked !! It's mostly plastic .

Dusterdude72

Similar....but not exact same symptoms.....I have factory IWE's (to my knowledge).new IWE solenoid,not losing vac when parked,And my humming noise doesn't fade the faster I go....it increases.

BUT, that doesn't mean that we don't have a similar issue....just not exactly the same symptoms is all.

Stay tuned to the thread and hopefully either someone will chime in with some helpful info....or when I get a chance to inspect it real well maybe I will find the issue...if I do I will be sure to report back!.

homer

Dusterdude72, if you can, unplug the vacuum hose at the IWE solenoid. For a short test, just leave it unplugged. This will force the IWE's to engage the hubs but your transfer case will stay in 2WD. See if the noise goes away then. I'm doubting it, but it's worth a check?

Dusterdude72

I have already disconnected each vacuum line from each IWE while the truck is running in bot 2 wheel drive aswell as in 4 wheel drive to make sure the vacuum was properly functioning .....which it is.

But I have not had the chance to disconnect the vacuum and drive it in both range selections to see if the noise is still there. I'll give it a try soon when this weather breaks.