Noise when in 4x4

[Mercmarquis]

My truck has shift on the fly 4x4. The other day I picked up my truck from the car wash and the guy must have bumped my switch on 4x4 high while wiping the dash. Drove down the block and my truck was making a very awfull screeching/ grinding noise until the front hubs unlocked. Looked and played around with it this afternoon. From what I can tell any time the front hubs are locked and in 4x4 mode the truck will screech most anytime its moving sometimes its intermittant but not very for very long. Even with the hubs locked by hand. Noise seems to be coming from the axle area. Everything seems to be working fine but that noise doesnt sound very good for the truck at all. Anyone have any ideas?

[Mercmarquis]

Well truck went into the dealer yesterday. I had them check everything out. U joints looked good. The hubs looked good but the tech said they were bone dry. He cleaned everything up, changed some seals and greased it up and so far no noise. I had the dust seals for the axle replaced in New Jersey, so maybe when everything was put back together someone forgot to grease it. Who knows, I have yet to work on 4x4 hubs myself.

Anyway everything works fine again. I'm glad it was just some grease. I was not looking forward to purchasing new hubs on a 50k mile truck cause they are not under the powertrain warranty.

[sinner6.0L]

could have been a vacuum leak too causing partial engagement