97 Explorer 4x4 Rear End whine

[mlunsford]

Hi all,,
I have about 90K on a 97 Explorer 4x4 and have noticed, since I sat in the back seat, there is a low whine to the rear end as speeds increase so does the noise.

The rear end has a small seal leak so I check it every now and then to make sure it says full. I use synthetic gear oil like the manuals says to.

Two questions:
1, as long as I keep gear oil in the rear end, is this something I really need to be concerned about ?
2. is there any additive I can do to bring the noise down, like use regular gear oil or an additive ?

Thanks

 

[ericautopart]

It's likely to be a pinion bearing or an axle bearing w/ no oil or grease will fix. I'd check it out before it wears a groove in your housing which will cost big bucks later on down the road.