4WD/Transfer Case/Front diff Banging and Grinding Noise

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I have been trying to diagnose an extremely loud grinding and banging noise for the past few weeks and I am at a loss. I am almost certain this is not an IWE issue as I have had both IWE's go out before and this is a VIOLENT noise and can be felt on my feet through the floorboard.

I first noticed the noise after having a fairly well known shop in LA do some work done on the truck. What I had done there:
- Driver side Spindle
- Steering tie rod ends
- 37's and pinch welds
- Front Brake pads
- Upgraded UCA bolts

The day after I got the truck back this intermittent noise started happening on the freeway. Went away for about 20 minutes, came back again.
I went back to the shop that worked on the truck and they recommended that I change the transmission mount because it was essentially torn in half. A different shop performed that work and I thought I was home free. About 3 weeks later (yesterday) the noise came back.

When I got home, I got under the truck and decided to play around with the idea that it might be the 4wd system. With the truck and engine turned on in 2wd, I put the transmission in nuetral and tried to rotate the Driveshaft going from the transfer case to the front diff and I was able to rotate it. I was also able to rotate the driver side CV shaft. I was not able to rotate the passenger side CV shaft. It very clearly felt like it was engaged and locked in.

Thismade me want to pull the vacuum lines from the hubs. both hubs were getting vacuum. Gave up for the night.

Today, I had already scheduled with yet another shop to do the trans fluid, gasket, and Lead frame, Had that done. Driving home from the shop the noise started on the freeway.

The noise happened 2 times yesterday and 2 times today. Each time i let it go for anywhere between 3 and 10 seconds and I shifted from 2hi into 4hi and as soon as I did, the noise would go away. I got back to 2hi and wait a few minutes of driving around and it would eventually come back.

What the actual hell is going on here?????

PLZ HALP




 
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OP
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Easy one IWE. Now that is the noise. Why???? IDK. Pull a vacuum on them. but the noise is the IWE.
@BigBlackRaptor
I got a vacuum test kit and will test tomorrow but again this is such a violent noise and does not match up with my 2 previous IWE issues I have already had. Its like the hulk is underneath the truck punching the floorboard. and very intermittent. Will happen for a few seconds and not show up again for days or weeks.
 

Gumby

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I got a vacuum test kit and will test tomorrow but again this is such a violent noise and does not match up with my 2 previous IWE issues I have already had. Its like the hulk is underneath the truck punching the floorboard. and very intermittent. Will happen for a few seconds and not show up again for days or weeks.
It is exactly how my friends F150 (reg) sounded and VERY violent. Happing on a 8 hour trip home from Louisiana fishing trip. I wasn't sure we would make it. LOL did the last 100 or so in 4 wheel. His wasn't the IWE itself but something in the vacuum system. fixed it for a while back to doing it again. so he said about a week ago. He going to bring it to the garage soon.
The more it partially engages.......The more violent it could be. I am no expert That would be my thought.
I can't say 100% I didn't do the first repair... he did it him self with YouTube. My option is it is in the vacuum system or the IWE them self.
 
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pat247

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Something else to check is the 13mm nut on the end of the front axles under the dust cap, they can back off and let the axle move in and out in the IWE.
 
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Alrighty, so some interesting findings.

Decided to go for a drive with a camera mounted to the underside of the truck to see if I could capture what was going on. I was monitoring the live video feed on my hour plus drive and the entire time, both CV shafts were spinning at wheel speed as well as the transfer case drive shaft.

No noise on the freeway, about 40 miles one way. I got to my destination and as soon as I hit uneven ground (gravel patch on the side of the road) the noise comes back.

Looking back at the video, the passenger IWE / CV seems to disengage at the time of the noise, and noise goes away after re-engaging (Big clunk noise).

Immediately I am thinking IWE after seeing video. I go back home and jack up the front of the truck to begin my vacuum test. Here are my readings starting from the beginning of the system and working my way down:

- Vacuum reservoir pulls vacuum - 25 inch pounds
- Check valve works (Brand new installed yesterday)
- Solenoid works (Brand new installed yesterday)
- Vacuum pressure measured at solenoid - 25 in pounds
- Used the hand pump to create 25 in pounds of vacuum at the top of the vacuum line where it connects to solenoid. Held 25 pounds for 2 minutes. Checks out, moving on.
- Turned truck back on. Pulled the vacuum line from both IWEs and it measured 25 in pounds on both sides.

Heres where it gets interesting.
Hooked up the vacuum to the IWE directly and maxed out the hand pump at 27 pounds. Both IWEs will hold that pressure for 2 minutes BUT when I try to spin the wheel on both sides, the CV shaft still spins with the speed of the wheel, even with vacuum applied.


How in the hell do BOTH IWE's fail at the exact same time and have the exact same problem where seemingly no amount of vacuum will disengage them from the axles?
This makes more sense as to why both CVs and the transfer case drive shaft were all spinning in unison for my entire drive but I am extremely concerned with how much damage this may have caused.

Anyone hear of this happening before? @FordTechOne any ideas?


Heres the video

 

Gumby

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Great idea with the go pro!!!!! There it is, love it. Now.... I don't know if one is engaged if it will spin the other and the transfer case drive shaft. My thoughts are yes? but don't know for sure. FTO should. Agin good call on the go pro!!!
 
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