2005 Explorer Rear Noise

[mewoods]

This is my first post.
I have a 2005 Ford Explorer XLT 4 wheel drive.
I have the notorious rear end howl that most explorers have.
When I let off the gas and start slowing down I can hear a noise like a grinding sound.
Its not very loud, but definitely noticeable. .
Could it be a hub bearing? I pulled the right wheel and rotor off and I don't notice any slack in the hub. Any suggestions on what it could be?

 

[cross6]

It might be the rear end. Bearings go out in those, too. Mine has been replaced twice in 187K miles.

With the rear jacked up and truck in neutral you should be able to feel the rear wheel hub bearings if they're grinding. Either spinning by hand or wiggling the wheel. You can put a mechanics stethoscope, or long screwdriver to the hub and listen as someone turns the hub.

You can also try draining the rear end. If the old oil is shiny or leaves glitter at the bottom of the drain pain then it's probably the rear. Changing the oil out with some good synthetic 75w-140 didn't quiet it down, but did change the noise enough to let me know it was definitely the rear. Only made noise when I let off the gas.

 

[imp]

Finally! Someone else proposes a stethoscope to accurately locate noise sources! Beats guesswork, and replacing good parts by mistake!

I've recommended this a number of times, but never got a response. In my case, from past experience, I was almost certain my noise source was differential side-bearings, but was wrong! The steth. proved the noise came from a wheel bearing! Unfortunately, nothing could be heard by turning the shafts by hand; thus, on jackstands, in "4WD HIGH" (2004 w/"4WD AUTO"), my wife ran it up to 20 mph, and that allowed good diagnosis. Can't be done in 4WD HIGH as the speed differences of front and rear due to unequal brake drag (always present) causes chattering of the electronic transfer case clutch.

imp

 

[mewoods]

Ok... so I got the rear tire and brake rotor off. The right side is harder to turn than the left. It doesn't seem to have any slack in the hub. Also, should I be able to turn the rear end with the transmission in park? It spins in neutral and in park.

 

[Dave8338]

The wheels will spin freely in park or neutral. If you can rotated he drive shaft when in park, you have a serious problem.

 

[cross6]

I think he means he can turn the CV shaft with the tranny in park. With an open rear end and both rear wheels in the air and the tranny in park, if you spin one CV axle the other side will spin in the other direction.