Rear End Failure

[Lightning Struck]

I've been pretty vocal about the continued issues I've had with the rear differentials in these. My first rear end went at 33k miles, replaced under warranty. 6 weeks ago the 2nd rear end went at 69k miles(only lasted 36k), which Ford was willing to help with if I waited until the parts were off national backorder. I found a rear end assembly in Hermann Mo, however my dealer quoted me that shipping would be $675 almost the price of the rear end itself! I took my Explorer back from the dealer(who was going to charge almost $2000 in labor alone for this job), ordered the rear end from Missouri (UPS ground was $120 and got here in 2 days), 2 new halfshafts, and 2 axle nuts. I then proceed to download and print all the pertinent service manual tidbits off another explorer site.

All told this wasn't that bad of a job. The hardest/slowest part was the driveshaft. I had to make a tool that mimics the ford specified puller tool, and then take almost every bottom cover off the car. Having done this once, I would say to do it again would be a maybe 4hr job. Both wheel knuckles come off, halfshafts pry out, remove driveshaft, pull the 4 bolts(or 3 for some of you), and reverse.

Now to the failure. The symptom was an extremely leaky driveside halfshaft seal.. The real cause was a catastrophic bearing failure. I was told be a local sheriff that his department has had failures, with a few causing complete seizure and I can believe it.

 

[Stone17]

What does the ford specified puller tool look like?

 

[Lightning Struck]

What does the ford specified puller tool look like?

 

[Cruising68]

Just an fyi, you can weld a exhaustclamp to some square tube and add some square tube at a right angle to bang on.I made one up in about ten minutes and it works well.

Sent from my iPhone using Tapatalk

 

[Lightning Struck]

I did something similar. Used a exhaust clamp u-bolt, some angle iron, some 3/8 keystock and a large nut. I had to buy the keystock anyways, to pull the dang fill plug out of the diff, since there's not enough clearance for a ratchet.

 

[scoobysportD]

How did you know the rear end was going? Was it with a bang or a slow process?

 

[Lightning Struck]

How did you know the rear end was going? Was it with a bang or a slow process?

It tore the output shaft seal and was pumping fluid out the drivers side

 

[scoobysportD]

It tore the output shaft seal and was pumping fluid out the drivers side

Any noises or other things you noticed? Or was it an oilstain on the driveway?

 

[amiller5103]

I've been pretty vocal about the continued issues I've had with the rear differentials in these. My first rear end went at 33k miles, replaced under warranty. 6 weeks ago the 2nd rear end went at 69k miles(only lasted 36k), which Ford was willing to help with if I waited until the parts were off national backorder. I found a rear end assembly in Hermann Mo, however my dealer quoted me that shipping would be $675 almost the price of the rear end itself! I took my Explorer back from the dealer(who was going to charge almost $2000 in labor alone for this job), ordered the rear end from Missouri (UPS ground was $120 and got here in 2 days), 2 new halfshafts, and 2 axle nuts. I then proceed to download and print all the pertinent service manual tidbits off another explorer site.

All told this wasn't that bad of a job. The hardest/slowest part was the driveshaft. I had to make a tool that mimics the ford specified puller tool, and then take almost every bottom cover off the car. Having done this once, I would say to do it again would be a maybe 4hr job. Both wheel knuckles come off, halfshafts pry out, remove driveshaft, pull the 4 bolts(or 3 for some of you), and reverse.

Now to the failure. The symptom was an extremely leaky driveside halfshaft seal.. The real cause was a catastrophic bearing failure. I was told be a local sheriff that his department has had failures, with a few causing complete seizure and I can believe it.

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What was the cause of your first rear end failure?
I just had my rear end fail at 23k miles due to a failed pinion bearing. It was making a chunking noise from rear end and chunks of metal found when we drained the fluid. It’s under warranty and they’re rebuilding the rear end, I’m waiting for the parts list. Hoping they replace all seals and bearings at a minimum, maybe ring gear or others if damaged. Anyone know what’s in the ford rear end rebuild kit? Hoping this is a one off failure of that pinion bearing and I don’t see an issue for the remainder of the vehicle life.

 

[hbalek]

What was the cause of your first rear end failure?
I just had my rear end fail at 23k miles due to a failed pinion bearing. It was making a chunking noise from rear end and chunks of metal found when we drained the fluid. It’s under warranty and they’re rebuilding the rear end, I’m waiting for the parts list. Hoping they replace all seals and bearings at a minimum, maybe ring gear or others if damaged. Anyone know what’s in the ford rear end rebuild kit? Hoping this is a one off failure of that pinion bearing and I don’t see an issue for the remainder of the vehicle life.

After having the front CV axles/boot replaced, then the front axle disconnect actuator TSB, now my rear axle is lumpy, bouncey and noisey. I feel like it bounces more over bumps, acceleration is kind of lumpy, I'm gonna have the entire rear end, axle, differential and shocks inspected. I really don't feel safe driving it lately. I'm at 52,000 miles.

 

[musclecarman39]

What was the cause of your first rear end failure?
I just had my rear end fail at 23k miles due to a failed pinion bearing. It was making a chunking noise from rear end and chunks of metal found when we drained the fluid. It’s under warranty and they’re rebuilding the rear end, I’m waiting for the parts list. Hoping they replace all seals and bearings at a minimum, maybe ring gear or others if damaged. Anyone know what’s in the ford rear end rebuild kit? Hoping this is a one off failure of that pinion bearing and I don’t see an issue for the remainder of the vehicle life.

Same here, clunking noises from rear end. I took it to the dealership and was told the rear diff was eating itself, 2021 ST with 33,000 miles. They replaced the rear diff and drivers side axle as the boot was torn under warranty.

 

[hbalek]

Same here, clunking noises from rear end. I took it to the dealership and was told the rear diff was eating itself, 2021 ST with 33,000 miles. They replaced the rear diff and drivers side axle as the boot was torn under warranty.

My rear differential and transfer case/ptu were replaced back in early June at about 50,000 miles. The transfer case failed again just 3 months later. I think the differential is bad again too.

 

[enphor]

It is my understanding that the transfer case and differential are not indicated for routine maintenance (fluid changes). Do you suspect the "forever fluid" being as the culprit, quality , or design issue?

I plan on changing fluids at 30K intervals like I used to do my subarus.

 

[Cruising68]

It is my understanding that the transfer case and differential are not indicated for routine maintenance (fluid changes). Do you suspect the "forever fluid" being as the culprit, quality , or design issue?

I plan on changing fluids at 30K intervals like I used to do my subarus.

Forever fluid is never a good thing! Cheap insurance to keep things running good imo. I’ve seen plenty of ugly fluids. Worst are usually brake fluid and power steering fluid and CVT fluid. Most people never change them.


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[hbalek]

It is my understanding that the transfer case and differential are not indicated for routine maintenance (fluid changes). Do you suspect the "forever fluid" being as the culprit, quality , or design issue?

I plan on changing fluids at 30K intervals like I used to do my subarus.

My service advisor and powertrain technician said to drive it easy to allow the PTU to break in and clutches to adjust. For 500 miles I have never gone past 1/3 throttle or above 3000 rpm. It still shudders when front axle gets power but not as bad as before the last replacement. In the next month or so I'm taking it in to be looked at again along with routine maintenance. Like I said, ever since the FADA TSB the power is eating away at the PTU and rear-differential and who knows what else. It drives like a 15 year old, 200K miles truck or worse! The only thing they haven't replaced is the driveshaft, which may be the culprit or the transmission itself.

 

[enphor]

I find it hard

My service advisor and powertrain technician said to drive it easy to allow the PTU to break in and clutches to adjust. For 500 miles I have never gone past 1/3 throttle or above 3000 rpm. It still shudders when front axle gets power but not as bad as before the last replacement. In the next month or so I'm taking it in to be looked at again along with routine maintenance. Like I said, ever since the FADA TSB the power is eating away at the PTU and rear-differential and who knows what else. It drives like a 15 year old, 200K miles truck or worse! The only thing they haven't replaced is the driveshaft, which may be the culprit or the transmission itself.

I find it hard to believe stock power is destroying the ptu and diff so quickly even on replacements. Something else has to be going on. Driveshaft would be suspect , possibly bent, misaligned, causing damaging vibrations etc.

 

[hbalek]

I find it hard


I find it hard to believe stock power is destroying the ptu and diff so quickly even on replacements. Something else has to be going on. Driveshaft would be suspect , possibly bent, misaligned, causing damaging vibrations etc.

I think it's the FADA delete TSB. All these other problems started after that. Either they didn't perform the TSB correctly or something else is worn or damaged. I remember reading that the 2020 did have a driveshaft weld recall but mine wasn't recalled. My service advisor said the 4 cyl. 300hp and 6 cyl. 400hp engines both use the same PTU, which is unbelievable!

 

[RusW1]

good
morning all, I have a 21 ST, 11,700 miles and going on its second rear diff. car was initially looked at for a moan at high speeds, I have another thread out there regarding this, and the first thing they replaced was the rear diff. Upon inspection, they found chunks of metal and metal shavings in it. Once that was replaced, the noise was still there so they moved onto CV half then the rear driveshaft. Next was the front differential just about two weeks ago, still the noise. Now they inspected the rear diff again with less than 200 miles on it said there are more metal shavings in the new one. I am now on standby for Ford engineering to make some recommendations. Is it just crappy parts or what with these rear differentials? My vehicle is totally stock, as a matter fact, I have a whole pile of custom parts waiting to put on/if I ever get the vehicle back or we have a whole pile of brand new parts for sale if I just get rid of it anyone suffering similar issues so soon or have any ideas as to why the failures? rhanks

 

[hbalek]

good
morning all, I have a 21 ST, 11,700 miles and going on its second rear diff. car was initially looked at for a moan at high speeds, I have another thread out there regarding this, and the first thing they replaced was the rear diff. Upon inspection, they found chunks of metal and metal shavings in it. Once that was replaced, the noise was still there so they moved onto CV half then the rear driveshaft. Next was the front differential just about two weeks ago, still the noise. Now they inspected the rear diff again with less than 200 miles on it said there are more metal shavings in the new one. I am now on standby for Ford engineering to make some recommendations. Is it just crappy parts or what with these rear differentials? My vehicle is totally stock, as a matter fact, I have a whole pile of custom parts waiting to put on/if I ever get the vehicle back or we have a whole pile of brand new parts for sale if I just get rid of it anyone suffering similar issues so soon or have any ideas as to why the failures? rhanks

My dealer also had to put a second new differential on it but this time there's no more shuddering and vibration on acceleration. They said the differential was the wrong gear ratio. I've had the transfer case replaced twice and the differential replaced twice in past 4 or 5 months. Now I think it drives much smoother than after the previous repairs. All of these problems began after 40K miles and the FADA was deleted under the TSB issued for that.

 

[enphor]

good
morning all, I have a 21 ST, 11,700 miles and going on its second rear diff. car was initially looked at for a moan at high speeds, I have another thread out there regarding this, and the first thing they replaced was the rear diff. Upon inspection, they found chunks of metal and metal shavings in it. Once that was replaced, the noise was still there so they moved onto CV half then the rear driveshaft. Next was the front differential just about two weeks ago, still the noise. Now they inspected the rear diff again with less than 200 miles on it said there are more metal shavings in the new one. I am now on standby for Ford engineering to make some recommendations. Is it just crappy parts or what with these rear differentials? My vehicle is totally stock, as a matter fact, I have a whole pile of custom parts waiting to put on/if I ever get the vehicle back or we have a whole pile of brand new parts for sale if I just get rid of it anyone suffering similar issues so soon or have any ideas as to why the failures? rhanks

I'm wondering if this is some kind of alignment issue (or rather misalignment) of the drive shaft , diff mounts, etc, basically everything connected to the diff. Unless you won the worst lottery and got two terribly defective rear diffs I'm at a loss. Where the bearings screwed at all, which could/would cause such issues.

Misalignment of the driveshaft to the diff would cause vibrations, noise, premature failure, wear, etc