I have a 98 Explorer v8 AWD. I have a loud gear wine and loud vibration coming from the front end. The front diff has been rebuilt. If I remove the front driveling the noise and vibration go away. It seems to be coming from the transfer case, I have replaced the transfer case chain and the bearings and bushings. Does anyone have an idea of what this may be? My transmission shop seems to be at a loss

 

If the noise is confined to the front driveline system , did anyone check the lube level in the front differential?

 

Yes, the front differential is all new, bearings seals, everything but their is still the gear wing and a loud rumble when you get it warm and up to speed (around 50). With the front storyline out it is perfectly quiet

 

you may have a bearing that's going bad in the front end of the transfer case and causing it vibrate at speed or your front drive line is out of balance

 

What do you get with the driveshaft off and the front hubs locked.

 

with the front driveline off I have no noise or vibration. It is AWD so it has no hubs

 

after doing some research on other forums also I think it is the viscous coupling in the transfer case that has seized up and it causing the vibration at all speeds, you just cannot feel it at low speeds

 

it does have front hubs it is just a different type of hub. and you could be right about the viscous coupling