I have a noise that sounds like a bearing going bad.

If I place the system in Auto, the noise appears when it shifts into 4WD. If I place it into, 4WD it's constant. Maybe hubs or transfer case. The faster I go, the louder the whine. The X-case is full with the right fluid.

I noticed the front axle half shafts always turn. What enables the hubs to lock? If I can have the system in 4WD and without the hubs locked, it will tell me a lot. Yeah, I can take out the front drive-shaft but that's always a pain.

Any ideas?

 

make sure you don't have mismatched tires or tires with large differences in treadwear. tires with different rolling circumferences will cause this noise.


when you engage full 4wd, the tcase engages the front prop shaft. A signal is sent to the front diff actuator to engage the front axles.


In 2wd the front prop shaft should not turn. the front axles are freewheeling; not locked into the front diff.

 

Funny, I totally forgot about the actuators. Been so preoccupied.

Tires are proper.

I disconnected the plug to the axle actuator and placed the truck in 4WD. The hubs did not lock but you could hear the transfer case actuator engage the 4WD. The noise promptly came up. Crap.

 

I just posted a thread that relates to this one directly. I've been hearing a strange sound almost like a light hummm coming from the front end. We took it to the dealer and they said all was well. Didn't have any problems with the 4wd, but today I get out of work this morning and it's a snow storm today. Of course today is the day the 4wd s*%its the bed. I wouldn't drive the truck until you've figured it out for sure. I have yet to see the financial situation that is most certainly to arise at a high cost.

 

Mine sounds like a whirring sounds from under the truck. Sound level rises and falls dependent on speed.