Differential gurus, help? Squeaking and more..

[dacaur2]

So driving yesterday I started hearing a sound like when your brakes are completely worn down and the metal of scraping on metal. I was quite a ways from home so just resign myself to replacing the rotor when I got home. The odd thing is now and then it would grab and put a drag on the engine for a moment.
Finally something let go or something and there was a horrible grinding so I immediately pulled over and had it towed home on a flatbed....
Pull the tires and the brakes were all fine..... So I have my wife drive it slowly and I think the noise is coming from the differential. thing is it's not always the same noise and it doesn't always make noise driving along slowly.... Here is a video that starts out in reverse then goes to forward then back to reverse again then forward... also I can feel it through the trailer hitch when it makes the noise the squeaks and the klunks.. sorry 4 commentary and inconsistent camera, my wife was attempting to eject me from the rear of the explorer....


Secondly now I don't know if this is related, I was told that no 4th generation that the factory with mechanical limited-slip, but it sure feels like some kind of limited slip in here, or something I never actually did this test before I had the problem so I don't know if it's related or just something else.

One tire off the ground the other one is on the ground, transmission in neutral. if I turn the tire slowly it just keeps turning, but if I turn it fast it will catch and then I'll feel it release and I can turn it some more than I will catch and release then I can turn up some more. in the video I an pressing as hard as I can the entire time when doing it fast, its stopping on its own and I keep pressing. If I had to describe when it releases, its like a valve slowly opening then it will spin some more........ (Edit- after pulling the diff out and opening it up, definitely not limited slip. Seems the pinion bearings are bad. My theory is when rotating slow everything was fine, but when rotating fast it caused the pinion to move and allow the u-joint in the driveshaft to bind.... Doesn't make perfect sense, but it's all u can think of....)

 

[Explorer_PL]

When you pulled the wheels of, did you check the e-brakes as well ?
Maybe they fell apart inside the drum ?

Also, when you were turning the rear wheels, was the tranny in N and was the driveshaft turning asw ell ?

maybe the "catching" happens in the transfer case, just guessing ....

Pulling the rear cover would be my next step I think.

 

[dacaur2]

Yes the transmission was in N and the driveshaft was turning when I turned the wheel (other wheel was on the ground) I have not been able to get it to make any noise by turning the wheels by hand, tried both wheels one at a time off the gound as well as with both wheels off the ground (and the fronts just to cover my bases)....yea I pulled the rotor on the side it sounded like it was coming from and it looked ok. of course we are listening to it in sort of an ally, so sound can act weird. Ill pull the other when I get home today. Talking to my buddy at work he thinks the ebrake is the most likely culprit as well, followed by ujoints (less likley) if all that checks out I guess pulling the cover is my next step.... Mayby I will put the whole thing on jackstands and put it in gear and see if I can get it to make the sound then I could crawl around and find out for sure where its coming from...

I assume i need all 4 wheels off the ground to run it in gear or it will sense the rear wheels turning and fronts not and try to engage the transfer case coupler? Is there a fuse I can pull so I can safely do it with just the rears off the ground? Otherwise I need to buy another set of jackstands....

 

[Explorer_PL]

I always do it with all 4 wheels up. I nailed together few pieces of 6x6 and 4x4 lumber to create supports and that works great as it's very solid (I feel safer that way), or use 4 jack stands (less safer ).
When you have the car up, press the traction control button and hold it for 5 sec, that will deactivate the tc and you will not get all the jerking of the truck.

 

[dacaur2]

Well, I pulled the other rear rotor, and the parking brake on that side looks fine too.bi checked out the u-joints on the drive shaft, and they seem solid, but I think I might have found the problem. There is play in the pinion bearing. I can grab the driveshaft and move it up and down and I can see it move at the differential, "thunk thunk thunk thunk"....

 

[Tike]

Well, I pulled the other rear rotor, and the parking brake on that side looks fine too.bi checked out the u-joints on the drive shaft, and they seem solid, but I think I might have found the problem. There is play in the pinion bearing. I can grab the driveshaft and move it up and down and I can see it move at the differential, "thunk thunk thunk thunk"....

hows the center bearing look? might be creating a vibration or play into the rear ?