tjsand33

Hello! I recently took my truck off road and noticed it slipping/shuddering a lot when in 4x4. It only happens when the 4x4 is actively pulling/spinning tires or the truck is turning - no sound in 2wd. There is an obvious grinding sound/occasionally banging coming from the front left when turning left or when driving straight and slipping tires. The front end makes no noise when driving straight on dry pavement in 4x4 or on grass, etc when the tires aren't spinning. It will, however, make the noise when turning on pavement. I recently replaced the IWE solenoid and the hub actuators. I am familiar with their failure points and this is completely different. I'm thinking it is either related to an issue in the front gear box, front diff, maybe half-shafts, etc. Just curious if anyone else has experienced this or has input. Much thanks! Right now I'm dealing with about 3wd.

Rydar

Resurrecting an old thread. This exact thing is happening to me currently in a 2020 (I believe it's the same 4x4 system though). I recently had my IWEs replaced too. Did you ever figure out what was happening?

Laminar

I have the same thing - the front left "slams" once the tires slip in 4x4, and after that it seems to be engaged. But there's definitely a "crunch/clunk" before it locks in. New IWE as well.

Rydar

This WAS the exact situation I was in with the hard slam/crunch/clunk when slipping. While pulling into my driveway on my way home last time, it started doing this. As soon as it slips, you can hear what sounds like gears stripping (IWE maybe?)

[F2C]MaDMaXX

Super-necro, wrong generation truck, but that's horrible, sounds like the IWE's are being disengaged, at least partially.

Rydar

Yea I know it's the wrong gen, but I was under the impression the 4x4 IWE components are swappable so for this discussion it's not relevant. I could be way off though.

Another clue on this: The system seems to work as prescribed until a wheel slips (can't tell if it's ANY wheel or just the F/L wheel.... it seems to be any wheel) then the noise is heard and no power seems to be transferred to the front wheels. The whole system seems to work as normal when in reverse too. 4A and 4H have the exact same symptoms.

[F2C]MaDMaXX

You should check engagement - get the front wheels up off the ground and start it in 2H, rotate front wheels forward and backward, watch the axles for turning and listen for sounds.

Rydar

Hadn't got around to doing that until today. Did this with the truck off and IWE hose pulled so there couldn't be any pneumatic pressure in the lines. The wheel spins, you can hear the clicking/grinding in the hub, and the CV axle doesn't move. Connected the hose again and tried in 2H, 4A, and 4H..... no change. Both sides do the same thing. I'm really wondering what they did when they "replaced the IWEs"

[F2C]MaDMaXX

If you've got clicking when the axle isn't turning, then it's either binding at the IWE or the hub bearing has gone. Remember that engine off or without vacuum, the IWE should engage, the axle should turn. Does the clicking disappear when you apply vacuum with engine running in 2H?

Rydar

No, nothing seems to change it. Truck running in 2H, 4A, and 4H..... all the same thing. It's like the IWEs are stuck halfway engaged regardless of vacuum pressure. It's weird to me that both sides are the same way.

Remember earlier in the thread this started out as a HARD clunk any time the front tires slipped on snow/ice when in 4H, then progressed to this clicking/grinding. I haven't had the "hard clunk" since it started free wheeling.