Whining noise and clunking in 4x4 high

[Matty50]

Hello,

I'm new to the Explorer and 4x4 world, having owned one for only about 10 months. And up to the point I've really enjoyed my '03. But recently it got somewhat slick here and so I thought I would put it into 4x4 high. Everything was fine, until I turned a corner. Then I got this whining noise, (the only way I can describe it) that was there, only when turning. Once I got the parking lot at work I drove around a bit and when I turned a little sharper, the steering wheel started to shake and it felt and sounded like it was clunking along. In 4x4 auto, or normal driving, everything is great, no sound. I thought the sound was coming from the front, but my father in law rode with me the other day and I did it for him, and he said it sounded like it was coming from the back.
So I'm at a loss. I was thinking maybe transfer case fluid might be low. Where do I fill that up at? Underneath or under the hood somewhere? I looked and couldn't find anything under the hood.
Any ideas? I know that this is long and probably pretty stupid stuff, but I would like to be able to try some things before I have to take this in to the dealer. I have a '03 XLT with 37k on it. (So Ford warranty is out, but I think my extended warranty will work. Just haven't checked on that yet.)

Thanks for your time and being patient with my question.
Joel

 

[TPLYNCH]

Were the road and parking lot completely snow covered? If not, the noise you were hearing is normal driveline binding being released. DO NOT use 4x4 HI or LOW on pavement or hard pack surface. If the tires cannot slip easily (to much grip on the road), tension builds up in the drive train because with the t/fcase lock, the front and rear wheels are all trying to turn at the exact same speed. When you turn, the front wheels travel farther (turn faster) than the rear wheels, which means the driveshaft is tryin to turn faster, but it can't because it is locked in with the rear driveshaft. If the front wheels can slip (lose grip) easily, this is not a problem. If they can't then the pressure builds until either the tire forcefully loses grip, usually with a jerk/bang, or you blow a cv or u-joint (really big bang :-()

 

[Matty50]

Thanks Tom. That's what I was hoping. I guess it just wasn't icy enough. So what would you say the rule of thumb would be for engaging the 4x4 high? Only in snow and not ice?
Sorry these seem kind of stupid questions, but I'm the newbie, so I'm just trying to get a feel for everything. Maybe I should have kept my Mustang!

One last question, where do I fill up the transfer case?

Thanks again for you response.
Joel

 

[TPLYNCH]

Auto is usually good enough for most situations. My rule of thumb is not to put into 4hi until the road is completely covered.

The fill plug for the t/f case is near the top of the case. Don't confuse it with the drain plug.