2019 Ranger - Rear Differential Failure

[JeffWoodall]

I'm just ribbing you, but it might be true. Oddly, I have just finished up some research on gear oils, and from what I can tell, the weight is not the factor to look for. Synthetic vs conventional mineral lubrication is a more serious topic when it comes to differential gears. Ford apparently was having trouble with contemporary synthetic 75w90 hence the conventional mineral 80w90 recommendation. That is all hearsay, but it would make sense if you start to follow the data.

The recommended weight gear oil for our trucks *80W90* typically has a kinematic viscosity@40*C of 135-165 cSt, i.e an ISO 150 gear oil grade. Our Motorcraft 80W90 has a kinematic viscosity@40*C of 146 cSt. Amsoil SG 75W90 has a kinematic viscosity@40*C that is too low @ 109 cSt, i.e. an (lower) ISO 100 grade. Amsoil synthetic 80W90 has a kinematic viscosity@40*C of 120.2 cSt, which is still too low. Even If you are going to replace the recommended Motorcraft 80W90 with Amsoil SG 75W110, it only has a kinematic viscosity@40*C of 132.6 cSt! It gets close to the 135 cSt of a recommended ISO 150 grade gear oil, but still no cigar.

Our M220 differentials and gears seem to need ISO 150 grade gear oil with a kinematic viscosity @40*C of at least 135 cSt.

I thought I was smart until I read this......I need to take a nap now.

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[VegasRanger]

I'm just ribbing you, but it might be true. Oddly, I have just finished up some research on gear oils, and from what I can tell, the weight is not the factor to look for. Synthetic vs conventional mineral lubrication is a more serious topic when it comes to differential gears. Ford apparently was having trouble with contemporary synthetic 75w90 hence the conventional mineral 80w90 recommendation. That is all hearsay, but it would make sense if you start to follow the data.

The recommended weight gear oil for our trucks *80W90* typically has a kinematic viscosity@40*C of 135-165 cSt, i.e an ISO 150 gear oil grade. Our Motorcraft 80W90 has a kinematic viscosity@40*C of 146 cSt. Amsoil SG 75W90 has a kinematic viscosity@40*C that is too low @ 109 cSt, i.e. an (lower) ISO 100 grade. Amsoil synthetic 80W90 has a kinematic viscosity@40*C of 120.2 cSt, which is still too low. Even If you are going to replace the recommended Motorcraft 80W90 with Amsoil SG 75W110, it only has a kinematic viscosity@40*C of 132.6 cSt! It gets close to the 135 cSt of a recommended ISO 150 grade gear oil, but still no cigar.

Our M220 differentials and gears seem to need ISO 150 grade gear oil with a kinematic viscosity @40*C of at least 135 cSt.

I changed my rear diff oil out at 5K. Was pretty dirty and the magnet did have some gunk but nothing crazy. I always do rear diff fluid change early on in my new vehicles. It’s cheap and I do it myself so why not. Now on your original post, got me thinking. I did switch to Amsoil because my Amsoil guy gave it to me for free. Do you think I should switch it back to the factory non synthetic factory oil or do you think I’ll be ok?

 

[Superdannyboy]

Is this a common thing on here to replace the diff fluid right after getting the truck? 1,000 miles really?

Changed mine at almost 40k. Disgusting and smelled like swamp butt. Looked silvery black and gooey.

 

[Vitis805]

I changed my rear diff oil out at 5K. Was pretty dirty and the magnet did have some gunk but nothing crazy. I always do rear diff fluid change early on in my new vehicles. It’s cheap and I do it myself so why not. Now on your original post, got me thinking. I did switch to Amsoil because my Amsoil guy gave it to me for free. Do you think I should switch it back to the factory non synthetic factory oil or do you think I’ll be ok?

I say go back to the conventional 80W90 unless you are getting the diff near 100C (212F) a lot of the time I.E. towing a lot up terrain or severe off-road duty. At that point you need 75W140 for the viscosity at spikes in higher loads and temps. From the research I have done, diffs during normal operation and light towing (above 40C) don't get near 100C so you don't need a 140 viscosity as that will increase drag over 80W90 at regular operating temp, but a 75W90 synthetic doesn't have as much viscosity for protection at lower temperatures I.E. start-up and cold running (40C and below). You would think that a synthetic 75W110 would have the viscosity at lower temperatures over 80w90, but the data has proven otherwise. Conventional 80W90 is always above 135 cSt @40C, while the best synthetic 75W110 falls short at 132 cSt @40C.

 

[VegasRanger]

I say go back to the conventional 80W90 unless you are getting the diff near 100C (212F) a lot of the time I.E. towing a lot up terrain or severe off-road duty. At that point you need 75W140 for the viscosity at spikes in higher loads and temps. From the research I have done, diffs during normal operation and light towing (above 40C) don't get near 100C so you don't need a 140 viscosity as that will increase drag over 80W90 at regular operating temp, but a 75W90 synthetic doesn't have as much viscosity for protection at lower temperatures I.E. start-up and cold running (40C and below). You would think that a synthetic 75W110 would have the viscosity at lower temperatures over 80w90, but the data has proven otherwise. Conventional 80W90 is always above 135 cSt @40C, while the best synthetic 75W110 falls short at 132 cSt @40C.

Even if the Amsoil I switched to is 80W90, I should still switch to conventional?

 

[Vitis805]

Even if the Amsoil I switched to is 80W90, I should still switch to conventional?

I would, personally. As I mentioned in the first post, the viscosity of Amsoil SG 80W90 @ 40C is below the viscosity threshold of a 150 grade oil. Motorcraft 80W90 meets that particular threshold.

 

[VegasRanger]

I would, personally. As I mentioned in the first post, the viscosity of Amsoil SG 80W90 @ 40C is below the viscosity threshold of a 150 grade oil. Motorcraft 80W90 meets that particular threshold.

thank you

 

[jflogerzi]

Bronco is nice, truck feels...heavy? The soft top is noisy at highway speeds but quiet otherwise. Fuel economy is proving to be worse than the ranger thus far.

Not surprised. Its a giant box

 

[JJG]

Hey Team,

Figured I'd share my experience. Please read the entire post here before hammering away. My 2019 Lariat Ranger, with 35,700 miles had catastrophic rear differential failure. Before the information, here is some relevant information.

Never towed
Hauled once (A 400 LB, four-cylinder motor on a pallet 20 miles)
Never went to a drag strip.
I don't think this failure was caused by a fluid failure

Heres the story, at around 1,000 miles, I drained my rear differential, front and PTU, and refilled all with appropriate Amsoil fluids, specifically the rear got 75w90 SVG in the correct amount (3.70 Pints or 2.2 Quarts).

I once again at about 30,000 miles decided to see how things were wearing in, dumping the front differential, PTU and Rear differential. The front and PTU units, I could have reused the fluid, they looked exactly as you would expect. The rear differential was not healthy. It had several chunks of metal on the magnet, I did not photograph this or save the shavings and I regret not doing that.

Now I am a guy who doesn't drive around in dead silence, I listen to podcasts, Pandora or Spotify, or have conversations on the phone. My work has me up and down the eastern shoreline from the Philadelphia area to around Northern Virginia, I drive a good amount of time for work in my personal vehicle and enjoy doing it. But with the discovery of the rear differential issues, I decided to start listening more to the vehicle and less to other sounds.

I couldn't tell any differences in noise, nothing noticeable until about 40-50mph, in that specific range you could hear a high pitched, and almost silent whine. This was present on acceleration and deceleration. With this I scheduled an appointment at my dealer and took the ranger in, the dealer was able to agree they could hear something but wasn't sure it was anything of consequence and told me that the vehicle drove fine (great actually) and sent me on my way. (They also serviced my transmission, replaced the filter and fluid, and noted no issues, or clutch material on the filter and said the fluid was in pretty good shape)

I decided that I was going to drive another 5k miles and then dump and inspect the fluid again, this time I took pictures and saved the shavings for the dealer, as when I dumped the magnet side, it had way too much wear. With my new evidence I returned to my dealer and told them I'd pay the cost if nothing was found, but confident something was, they popped the rear differential cover and discovered that the entire unit was grenaded. I don't have pictures, or much for details, but it was described to me that the differential spider gear pin, had almost sheared entirely in half (was barely in place) and that metal debris had damaged everything from the casing to the pinon, axles, everything. Parts are on back order, and in the meantime, I've been loaned a 2021 Bronco with less than 1k miles.

The dealer is taking care of the issue, which is great, and from what I've gathered this isn't a widespread or heavily reported issue. My guess is that my rear differential had a metallurgical failure, or was assembled on "A Monday morning, or Friday after lunch" although I have no proof of those things obviously being true or false.

My vehicle is modified as described in my signature, but I don't bash on my truck, I do a lot of highway miles, and have other vehicles that I joy ride.

Figured i'd share my story, and give you all something to read. Thanks, Anthony

Did you add the Ford friction modifier to the gear oil for the rear dif?

 

[landiscarrier]

I changed my rear diff oil out at 5K. Was pretty dirty and the magnet did have some gunk but nothing crazy. I always do rear diff fluid change early on in my new vehicles. It’s cheap and I do it myself so why not. Now on your original post, got me thinking. I did switch to Amsoil because my Amsoil guy gave it to me for free. Do you think I should switch it back to the factory non synthetic factory oil or do you think I’ll be ok?

I changed my front and rear. Rear was filthy. Front was pretty clean. Replaced with Amsoil (no I’m not in the cult) and I am having zero issues. Runs fine. No additional noise, whining etc

Also changed the transfer case fluid and transmission fluid.

Failures happen. Even if you follow every manufacturer spec exactly. Like the saying goes “shit happens”.

You can do what you want but I certainly would not be going back to conventional.

 

[JesseS]

In the amsoil cult it is important to get the manufacturer-specified fluids out of the vehicle as quickly as possible.

I always switched my Motorcycles over to Amsoil at the 1st recommended oil change interval, and never had engine, tranny. or rear drive issues in any of them (been riding for 60 years). And some of those bikes had 120K to 150K miles when I sold them. But I was sure to use the correct grade and high end filters. If Ford recommends 80-90w then there is a reason for it,

 

[VegasRanger]

I changed my front and rear. Rear was filthy. Front was pretty clean. Replaced with Amsoil (no I’m not in the cult) and I am having zero issues. Runs fine. No additional noise, whining etc

Also changed the transfer case fluid and transmission fluid.

Failures happen. Even if you follow every manufacturer spec exactly. Like the saying goes “shit happens”.

You can do what you want but I certainly would not be going back to conventional.

Yeah I am not set it on, I just like hearing people's opinion and learning different perspectives. I went with Amsoil because I got it for free and I was going to change the rear diff oil no matter what, so I changed it with the Amsoil.

 

[VAMike]

I always switched my Motorcycles over to Amsoil at the 1st recommended oil change interval, and never had engine, tranny. or rear drive issues in any of them (been riding for 60 years). And some of those bikes had 120K to 150K miles when I sold them. But I was sure to use the correct grade and high end filters. If Ford recommends 80-90w then there is a reason for it,

I don't use amsoil, vehicles still work fine. Nothing like a good anecdote war!

 

[Amsoil guy]

Just working off the spec list, I recalled that number in my original post from memory. I remember my rear diff took around 2 quarts of fluid before it wept out of the fill hole.

You’re correct. Mine took about 2.2q as well.

 

[tygr2007]

Hey Team,

Figured I'd share my experience. Please read the entire post here before hammering away. My 2019 Lariat Ranger, with 35,700 miles had catastrophic rear differential failure. Before the information, here is some relevant information.

Never towed
Hauled once (A 400 LB, four-cylinder motor on a pallet 20 miles)
Never went to a drag strip.
I don't think this failure was caused by a fluid failure

Heres the story, at around 1,000 miles, I drained my rear differential, front and PTU, and refilled all with appropriate Amsoil fluids, specifically the rear got 75w90 SVG in the correct amount (3.70 Pints or 2.2 Quarts).

I once again at about 30,000 miles decided to see how things were wearing in, dumping the front differential, PTU and Rear differential. The front and PTU units, I could have reused the fluid, they looked exactly as you would expect. The rear differential was not healthy. It had several chunks of metal on the magnet, I did not photograph this or save the shavings and I regret not doing that.

Now I am a guy who doesn't drive around in dead silence, I listen to podcasts, Pandora or Spotify, or have conversations on the phone. My work has me up and down the eastern shoreline from the Philadelphia area to around Northern Virginia, I drive a good amount of time for work in my personal vehicle and enjoy doing it. But with the discovery of the rear differential issues, I decided to start listening more to the vehicle and less to other sounds.

I couldn't tell any differences in noise, nothing noticeable until about 40-50mph, in that specific range you could hear a high pitched, and almost silent whine. This was present on acceleration and deceleration. With this I scheduled an appointment at my dealer and took the ranger in, the dealer was able to agree they could hear something but wasn't sure it was anything of consequence and told me that the vehicle drove fine (great actually) and sent me on my way. (They also serviced my transmission, replaced the filter and fluid, and noted no issues, or clutch material on the filter and said the fluid was in pretty good shape)

I decided that I was going to drive another 5k miles and then dump and inspect the fluid again, this time I took pictures and saved the shavings for the dealer, as when I dumped the magnet side, it had way too much wear. With my new evidence I returned to my dealer and told them I'd pay the cost if nothing was found, but confident something was, they popped the rear differential cover and discovered that the entire unit was grenaded. I don't have pictures, or much for details, but it was described to me that the differential spider gear pin, had almost sheared entirely in half (was barely in place) and that metal debris had damaged everything from the casing to the pinon, axles, everything. Parts are on back order, and in the meantime, I've been loaned a 2021 Bronco with less than 1k miles.

The dealer is taking care of the issue, which is great, and from what I've gathered this isn't a widespread or heavily reported issue. My guess is that my rear differential had a metallurgical failure, or was assembled on "A Monday morning, or Friday after lunch" although I have no proof of those things obviously being true or false.

My vehicle is modified as described in my signature, but I don't bash on my truck, I do a lot of highway miles, and have other vehicles that I joy ride.

Figured i'd share my story, and give you all something to read. Thanks, Anthony

Same issue, quoted ~$4,500 from the dealer to fix it. An entire rebuild is needed. 20,000 miles. Lifted, oversized tires, and a lot of abuse from me. I can't expect it to last forever. I will definitely do it myself, because the bill is insane for a rebuild part that costs ~$800. The stealership charged me near $300 for just taking out the drain plug and telling me it had metal chunks.

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