Rear diff noise - fix it or ignore it?

[usa1]

I took my 2004 Explorer XLT into a shop to look at an issue with a squeak in the engine compartment. They noticed during their road tests what they thought was excessive noise from the rear differential. They checked the oil and found it was in very bad shape (smelly, black, etc) and there were metal shavings in it. They did not remove the cover to see the condition of the gears, but recommended a gear change based upon their oil/shaving observations and knowledge of the issue on other Explorers. Cost of repairs is about $1,100. They are a good shop, so I have no reason to think they are scamming me.

The Explorer just passed 100K miles and is not driven a heck of a lot now. It's used mainly during bad snow conditions and I do a bit of towing (less than 3500 pounds), but not often. I have no aspirations of keeping this vehicle indefinitely, but would like it to be reliable for another 2-3 years.

The noise they mentioned from the rear is not one that I noticed, even though I was on the lookout for it when I purchased the Explorer a few years ago.

Knowing my situation, would you guys recommend a simple oil change on the diff and wait until the noise gets worse or do you think the metal shaving in the oil is a sign of a possible catastrophic failure coming up and warrants the $1,100 repair now?

Thanks in advance for the advice!

 

[chopperb]

If you dont hear a whine/hum coming from the rear just change the lube and ignore it.

 

[2Trux]

Pull the cover, look for damage, clean out old oil/junk, replace cover, drive for a few hundred miles, recheck oil.

I think that the key is to get everything cleaned out before replacing the oil.

 

[pet575]

I've driven with a whine/hum for more than 100K miles. It has gotten no worse and I've had no performance issues. I'd say drive it until you absolutely have to replace it. Light duty for 2-3 years seems like it should be fine.

 

[usa1]

Thank you for the advice!

 

[HiImBrian]

pull the cover, look for damage, clean out old oil/junk, replace cover, drive for a few hundred miles, recheck oil.

I think that the key is to get everything cleaned out before replacing the oil.

this^^^^^

 

[Dave8338]

I'm another that has lived with the bad ring and pinion noise for 100K. It HAS gotten to the point that I'm rebuilding the rear diff completely within a week or two. I can now feel slop at the rear end and don't want the thing to let go when I need it most. My .02

 

[imp]

Gear Noise

Whine or hum from gears can have several causes: One, slight misalignment of gear setting has occurred due to a differential side bearing or pinion gear bearing (less likely of the two) going bad. Two, gear tooth surfaces have become damaged due to lack of sufficient lubrication; this will likely also have affected the bearings. Three, gears are worn due to heavy long-term loading, such as trailering.

The range of noiseless operation of this type of gearing regarding gear "settings" is only a couple of thousandths of an inch, thus once tooth contact location or backlash (clearance) amount become out of range, hum or whine begins. Depending on the cause, noisy gears often CAN be driven for thousands of miles, but, for the majority of folks whose rear ends begin to howl, a disastrous failure CAN happen if the cause of noise is not determined. imp

 

[roush9799]

I'd just run it until it starts acting funny. It's not gonna cost any more to fix it and you may get 10's of thousands of miles out of it yet.

 

[usa1]

I changed the rear diff oil last night. Turns out the oil had very fine metal particles in it, but no shavings or evidence of unusual wear. The magnet on the fill plug was coated with metal particles, but I'd expect that after 100K miles. I could visually check the main gear through the drain hole and it looked fine with no nicks on any gear. I could feel or see any evidence of metal parts on the bottom of the differential, so I filled it back up.

Much ado about nothing it seems. I'm disappointed by the shop's recommendation, but glad I changed the fluid. The instructions available on this website were excellent and made it easy.

Thanks again for the advice. It helped me save $1,100!

 

[pet575]

I don't think your shop is out of line in their recommendation. It IS a known problem on these vehicles and they probably had that in mind. As stated above, you can drive it until you notice it "acting funny" or whatever you want to call it. That was my plan but then it never acted funny very often or got worse when it did.

I think you probably did the right thing and will be fine if you just keep monitoring it. I don't think I'd part ways with the shop over it, though.