Binding/Grinding Noise from Rear when Turning slow

[firefly1246]

So first off, I have done a ton of research trying to pinpoint my problem. I know there are a high amount bearing problems and differential problems with this model. I have a 04 explorer v8 4x4 with the towing package and limited slip 3.73 gears and 117k miles.

I am getting two different sounds, one is a random high pitch squeak from the left rear for the last 3 years ( done ~45k miles). It literally occurs randomly, sometimes no bump, other times when I do go over bumps. It also sometimes occurs when the transmission shifts. I can only hear it when the windows are down.

More recently (last 15k) I get a grinding/binding noise when I turn sharp at low speeds, ie maneuvering in the parking lot or turning from a stop sign. It only occurs when everything is warm, ie when vehicle has been baking in the summer sun or after driving for a while. If the vehicle is cold it sounds perfectly fine. I don't believe it is my bearings as I don't hear any noises that vary with speed when rolling down the highway, other than the normal differential whinning noise. I also don't hear any noises in all other driving. I have replaced the rear diff fluid with royal purple 75w140 and friction modifier, it made the whinning sound quieter, but didn't affect the low speed turn grinding/binding noise. I have verified all of my bushings and ball joints and get zero play in all 4 wheels. All of the sway bar body mounts have been replaced and thoroughly greased (multiple times, just in case). I have also replaced upper front ball joints with moogs.

I have found TSB 06-04-04 http://www.modularfords.com/threads/68546-TSB-06-04-04-Limited-Slip-Axle-Chatter-Shudder-Binding-Sensation-Or-Vibration-Duri

What I don't want is if my diff is going is to have to replace ring and pinion (I would rather do it early with just bearings/new clutch packs like this guy 200k+ http://www.explorerforum.com/forums/showthread.php?t=390430

I am currently upgrading front brakes to aviator brakes, which require the aviator front knuckle. So I will be replacing the front wheel bearing while I have it apart (as mine are still original). I plan on going OEM Motocraft or Timkin.

So question is...

1) Any idea on the high pitched random squeak? any way it could be rear wheel bearing...
2) Ideas on the grinding/binding noise from the rear, is it diff or rear wheel bearings.
3) If it is rear diff, is it worth doing now or wait till later?
4) If I need to rebuild diff, anybody know of a good write up. I want to do the work myself. I would also be looking for the right parts to buy.

Any help is greatly appreciated. I love my explorer, just don't love the nasty noises.

 

[firefly1246]

I didn't put the ford friction modifier in the diff as the royal purple already had friction modifier. Anyone think, this binding is due to the limited slip?

Thanks!

 

[zoewagner]

--Moved to Explorer Sport Section---

Sorry my reply/question applies to my Sport so I moved it over there.....

 

[rrgone]

My LS rear end was doing that binding thing too during parking lot turns and backing out of my garage where I must make a sharp turn to get pointed towards the street. I noticed it got worse when I rotated my tires. They were at about 50K miles so I replaced all 4 and it's a lot better since.

 

[icepickjazz]

Not sure I can help you diagnose the problem but did research some of the fixes you mentioned. See my response to http://www.explorerforum.com/forums/showpost.php?p=3219137&postcount=2