Why are there so many rear diff bearing failures on the 2002-up Explorers?

[Cobra Jet]

Just curious as to why there are so many rear diff bearing failures on the 2002-up Explorers?

I've known about the failures for some time now, read many many threads not only on this site, but even other car sites where folks have posted up the problems - and the fact that my Father's 2003 V8 XLT also had to have the rear diff completely rebuilt w/ low miles....

What is the reason behind the high failure rate, even on new or low mileage Explorers? Was it due to improper gear fluid, cheap diff parts/bearings used, incorrect install from the factory, improper torque values, incorrect pinion shimming, etc???

I've never really seen a "reason" as to why there are so many diff issues w/ the 2002-up Explorers (regardless if V8 or V6). I've just seen/read about many of the problems associated (whining, grinding, humming, NVH, noise at certain mph, etc) and the fixes - but no real explanation as to why there is a high failure rate (especially on low mileage vehicles). It's definitely a wide spread and well known issue with many folks upset about even having to have their vehicle down for such a repair (and of course those folks who have had the rear diff serviced more than just once)...

So, what's the real story?

 

[Hitchhikingmike]

I believe I started a thread about this a while back, no one had a straight answer. I do know that half way through the first year of the production of '02 explorers ford switched the rear end oil to a different weight oil. I think this cured some but not all problems with the rear end.

My explorer has 46k miles on the original differential and oil. I was thinking I should replace the oil with some amsoil gear oil to delay this expensive repair.

I do not mean to put a cap on this thread, if anyone knows more spill the beans!

 

[Cobra Jet]

Thanks for the input!

No, I don't think you are capping the thread at all. I think many others would also like to know what's really up or why there is such a high failure rate on these diffs. I've read a few threads where folks have put in the 75/140 gear fluid and still are experiencing rear diff problems, so even though the gear fluid viscosity may have been a small "fix", I don't think it's the "cure all" if there are still many Explorer diff failures, including those beyond the first year 2002 production...

What brand of rear bearings are used in the production cycle of the rear diff, does anyone know?

 

[tomtinsley]

Thanks for the input!

No, I don't think you are capping the thread at all. I think many others would also like to know what's really up or why there is such a high failure rate on these diffs. I've read a few threads where folks have put in the 75/140 gear fluid and still are experiencing rear diff problems, so even though the gear fluid viscosity may have been a small "fix", I don't think it's the "cure all" if there are still many Explorer diff failures, including those beyond the first year 2002 production...

What brand of rear bearings are used in the production cycle of the rear diff, does anyone know?

 

[tomtinsley]

2002-2005 Exp Rearend

My theory is that Ford bought a whole boat load of poorly manufactured rearends and installed some in their 2002-2005 Explorers (and other Ford vehicles) and put the rest out into their parts supply system. I have had my 2003 Explorer rearend redone 3 times. Two times the rearend was replaced with factory rearends and the howling returned in a few thousand miles. They just replaced a bad rearend with a bad rearend from the Ford's parts system. The last time I had the Technical Support Bulletin (TSB) done and the rearend started howling in less than 2000 miles. My dealings with Ford's Customer Care has been an exercise in futility. They actually told me that the rearend howl (or hum) is normal for the 2003 model year and that nothing further will be done! After each replacement or repair the rearend did not howl-- only after a few thousand miles did the howl return. I think the 2002-2005 rearends were manufactured with an inadequate heat treatment on the gear teeth. A heavier lubricant like 75w-140 will work for a while, but sooner or later the howl will return!! I have given up and am just living with the noise!!

 

[Hitchhikingmike]

Do you suppose that we could find parts for our rear ends from another manufacture that ford has never laid hands on? Or are the only parts that fit our rear ends only available from Ford?

 

[Doubt Incarnate]

the 8.8 ford is a popular rear end, there is a lot of aftermarket for it. timken makes good stuff, smythe or napa, or any of the good parts stores should have the carrier bearings, and richmond likely has tough gears for it.

 

[Thelt]

Mine has 127k on it and has not failed yet. It does make some noise and may fail eventually. Keeping it serviced with the correct lubricants will help a lot.

 

[tomtinsley]

Yes, There are after market rear end parts available, but I am trying to find a company that sells assembled rear ends with a prototype track record of at least 100K miles with no noticeable howling. If you buy parts be sure to look at the tag on the inside of the driver's side door for the vehicle's "Axle Code". You will need this code (e.g. 45 is a 3.55 ratio) to make sure that your parts are compatible with your vehicle.

P.S. My wife graduated from TWU @ Denton

 

[m8r8j]

will a ford 8.8 rebuild kit work on a 3rd gen IRS diff?

 

[whitestang04gt]

I just rebuilt my 2002 mountaineer 117K miles, some noise, full of metal, after taking it apart the races where shot, most of them had spun in the case. I just rebuilt the entire thing the FORD 8.8 BASE bearing kit will work, also note that there is an UPDATED axle seal kit for these, very different than the original, its a one piece rather than a two piece. Should have mine running again next week will let you know the outcome.

 

[fordbluefamily]

Hello all,

We bought our 04 XLS new and im on the third rear end. The first one was a surprise to me and kind of snuck up. I knew it was louder than when I bought it, but didnt realize how much until my dad got his Explorer and I realized how quiet it was. That was at 50K. Second one at 60K and done in conjunction with a rear ABS sensor, and last one at 75K. The last one was not a replacement, but was rebuilt by the dealership. It took them longer than usual, but we are almost 90K and no hint of noise has returned.

My theory is that the 8.8 is notoriously noisy and has been for years, but when you solid mount the pumpkin in an IRS application, you transmit more of that noise to the cabin. My Thunderbird's with IRS and 8.8 are no different. If it comes back, I will just live with it until it grinds itself into oblivion.

 

[Phoenix99]

will a ford 8.8 rebuild kit work on a 3rd gen IRS diff?

Yup , but you dont need the needle bearings.

 

[XtremeRanger]

SO the gear sets for a Solid 8.8 will work in the IRS? What about the LS Diff? If I redo my GFs, could I put a LS unit from the Solid 8.8 it it?

Maybe i should "search" this.......

Also, Is there any harm in just letting the thing go? She does mostly City driving and never really is up to 60+ for morte then 5 mins or so. If we go out of town or anything we take my 37MPG Satty:. so we could really live with the roaring. It sounds like the BFG tires on it tho....

 

[ummduh]

The gearsets will.

The carrier will NOT, due to the clips in the IRS axles. The non IRS carriers do not have provisions for those clips. Hence, there will be nothing holding the axle in.

Bearings I would assume are the same, but honestly do not know. I can find out though.

 

[Phoenix99]

Bearings , gears , shims , clutches are the same , basicly everything internal is the same. But you cant swap the whole thing (solid vs IRS) without heavy modifications.

 

[tomtinsley]

Ford Expl 8.8 IRS Rear End

I need to know specs for 2003 4x4 Eddie Bauer IRS rear end so that I can purchase a rear end assembly that hopefully does not have parts supplied by Ford!
Here's what I think that the specs are:

Rear End Ratio 3.55 (Axle tag on my door is 45)
Rear End is: 8.8 Independent Rear Suspension
Number of Splines: 31

The above are all the specs I need to buy what I want--right??

I have had rear end done three times on my EB 2003 Expl. The result is always the same-- the rear end hum returns after a few thousand miles. I still think there is something wrong with the mfg process of the gears like inadequate heat treatment on the gear faces.

 

[dannyb420]

I had mine replaced 3x with under 20k miles, still howls.

 

[Hitchhikingmike]

I had mine replaced 3x with under 20k miles, still howls.

hmmmm, this is not right. Some where your rebuilder is getting inferior parts. I don't know what you can do differently on the next rebuild though. But my '02 explorer now has 47k miles and the differential and has never made a the slightest noise, its the original differential and has never been touched by any mechanic. Perhaps my explorer is one of the few where ford actually built the differential right.

 

[dannyb420]

I think your right, my rebuilder was using inferior parts...my rebuilder was FORD. It was covered under the factory warranty. It still hums at 60 mph, if I go under 50 or over 60 its fine...so I go over 60, hehe. I think its a combo of a few things, Mine had to have the tranny recoded a few times, and the TSB for the diff fluid once after 1 rebuild. When you put a not-so-reliable tranny with a not-so- reliable rear end it can make for a difficult vehicle. But just as you said, some people have great results with theirs and never have problems.