Toasted 2007 Front Differential

[SuperSlabCab]

While towing in 2WD, the front diff started "Grunching"(Grinding/Crunching) today. I dont believe towing had anything to do with it. I have a Floor-Shift FWD, and no locks on the hubs. The service guy will call me tomorrow to tell me what happened. Ironically, the noise went away when I shifted into 4-HI. Does this sound familiar to anybody?

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[JMC]

The default setting for the front hubs is in 4x4. That way if there is ever a vacuum leak you will, in theory, still have 4x4 capability. When a vacuum leak occurs it will cause the front hubs to engage. If the leak is small enough the hubs will not fully engage and you will get the grinding sound. Towing has nothing to do with it.

JMC

[doctorD]

Originally Posted by SuperSlabCab

While towing in 2WD, the front diff started "Grunching"(Grinding/Crunching) today. I dont believe towing had anything to do with it.

I have a Floor-Shift FWD, and no locks on the hubs.

The service guy will call me tomorrow to tell me what happened.

Ironically, the noise went away when I shifted into 4-HI.

Does this sound familiar to anybody?

Yes, I had the same thing occur with my truck. JMC described in part what was occurring. I took it to the dealer and he said they've had several with these problems, but it was a simple fix. I'm not a mechanic so forgive me if what I recall sounds odd, but they said something about a solenoid and the vaccuum lines. The lines needed to be re-routed so they didn't get moisture in them as easily. If they do, it makes your front differential want to partially engage 4 wheel drive. They replaced the solenoid and re-routed my lines. It took about 40 minutes if I recall. I've not had a problem since then.

I'd say I had the problem occur about 3-4 times starting at 3000 miles.

[SuperSlabCab]

Thanks Guys!

Temps are getting crazy here in Phoenix, so condensate sounds credible.

I sent a link of this post to my service coordinator. The internet is a powerful tool.

[Redsoxfan]

I had the same thing, and they repaced a vac solenoid. There are TSB's about it. Try searching for the number on here.

[SuperSlabCab]

Just so you guys know,

The service manager printed our discussion out, and handed it to the mechanic.

He had to wait for the 'smoke machine', and then found a chaffed vacuum line, and fixed it in an hour. He did do some rerouting.

Thanks all,

[doctorD]

Great. Hopefully you will not have any further problems. I agree, the internet IS a powerful tool. This site is also an excellent tool.