Rear Differential Noise??

[joefnh]

I have a 2003 explorer 4.0L 4x4 with 100k on it and recently have been experiencing what can best be described as a whining or humming noise coming from the rear of the truck at highway speeds.

The noise immediately stops when I let off the gas and starts again when I press the gas. The noise does not change when changing lanes or turning. The question is is this a wheel bearing or differential.

I recently changed the front and rear differential oils with AMSOIL 75-90, this did not help the noise (transfer case and tranny too with AMSOIL). The old oil that came out of the differential was somewhat brackish in appearance with no significant metal paticles (I did filter it to see what might be there)

Any ideas?

If it is the differential what is the best way to have this fixed?

Thanks in advance

 

[joefnh]

Thanks MadMan, I agree I think it sopunds like the diff. As far as mechanical ability.. I have rebuit a few motors over the years. I just have not had to deal with the inner workings of a differential. By the way the seals are not leaking.

Does anyone know of any good sources of information on how to work on the differential?

--Joe

 

[bmilinski]

If you find an expert, I'd like to know how to remove a stubborn bolt from the rear differential "damper assembly". The bolt that runs thru the rubber grommet. Dealer said bolt will rust onto(weld) to rubber?? Never experienced anything like it !

 

[AP9]

If you find an expert, I'd like to know how to remove a stubborn bolt from the rear differential "damper assembly". The bolt that runs thru the rubber grommet. Dealer said bolt will rust onto(weld) to rubber?? Never experienced anything like it !

I've never tried this, but I remember in one of his videos jlsparky used a blow torch to melt the rubber when he couldn't get a bolt out of rear spring shackle for the same issue. I wouldn't think the differential damper would have that issue though, so try hitting it with a rubber mallet first.

 

[imp]

bmilinsky: I see in my Ford Shop Manual that a special tool is used to replace the pinion nose isolator bushing. It appears to sit in a pocket in the frame. However, nothing is said (of course) about removal of a stubborn bolt. Torque spec on it is 76 lb-ft; the two rear ones are 111 lb-ft.

It would seem that a good impact wrench ought to loosen the damn thing. If not, I would cut the bolt head off.

The special tool shown for installation has 6 parts to it. If the bushing itself is replaced, it must be installed with it's two location notches aligned in a fore and aft position.

If you think it will help you, let me know, and I will scan these two pages and post them. Tomorrow. Right now, I'm going to sleep! imp