2017~2025 Rear differential failure

Why would anyone want to stay with Mazda when rear differential is a common issue at under 100k miles, and the cost of replacement on average is $5500, never mind other accruing expenses? The response from corporate is beyond irresponsible.

 

[n0m0remazda]

 

[stickerbush]

Rear diff failure is not a common issue with these cars.

 

[wlong01]

Was the RD ever serviced? Did you drive through deep water?
Has to be more to the story then OP is posting.

 

[n0m0remazda]

Cx5 2017 manual does not list any service maintenence for fluid at any number of miles, only when vehicle is submerged, which it never was (CO and PA). Regular mazda dealership visits, and never once mentioned about rear differential oil replacement or issue until now. Why should the customer be responsible for Mazdas lack of accountability for proper maintenance. A cursory online search shows that it is an issue. The customer rep also did state it was an issue shes been getting calls about. The mazda dealership guy did admit that there was no maintenance details for this problem.

 

[wlong01]

Cx5 2017 manual does not list any service maintenence for fluid at any number of miles, only when vehicle is submerged, which it never was (CO and PA). Regular mazda dealership visits, and never once mentioned about rear differential oil replacement or issue until now. Why should the customer be responsible for Mazdas lack of accountability for proper maintenance. A cursory online search shows that it is an issue. The customer rep also did state it was an issue shes been getting calls about. The mazda dealership guy did admit that there was no maintenance details for this problem.

Yours is basically the first I've seen on this forum and I've been around since 2015. There was a post once but the car was driven through deep water.
If it was a problem I'm pretty sure there would be lots of posts on this forum.

 

[stickerbush]

My dealer suggested replacement of the diff fluid on my 2020 at around 50K miles. I complied with his suggestion.

 

[stickerbush]

@n0m0remazda how many miles on your CX5 when the diff failed? Do you know if the fluid level was ever checked? Did you do any towing (boat, trailer, etc.) with it?

 

[sm1ke]

I have had to get my rear differential replaced at 113k kms (70k mi) on my 2018 CX-9. I tried to take really good care of that car, but I had not replaced the rear diff fluid when this all happened - although I don't think it would have made any difference. In my case, the car saw very, very little "offroading", just a short climb up a dirt road here and there. Never towed anything, and I never pushed the car hard in the snow. 95% city/highway driven.

I maintain that a rear diff failure is rare, but not unheard of. There have been a few cases reported on Reddit and Facebook, and 2 or 3 other cases mentioned here besides mine (2 other CX-9s and 2 CX-5s, including yours).

For reference:

2016~2023 Thread 'CX-9 Rear diff failure at 113k kms (70k mi)'

Dec 5, 2024

I'm posting this to vent, but also to inform.

Back in January, I noticed that the car started making loud clunking noises. They were coming from the rear and seemed to be intermittent at first, but I soon realized that I could only hear the sound when the traction control light turned on and AWD was supposed to engage. I contacted my dealership to book a diagnosis appointment, but they seemed very skeptical that this was an AWD issue and assured me that if there was an issue with the rear diff or the AWD system, I'd have a warning light on the dash (there are no warnings or lights...

• sm1ke
• Replies: 32
• Forum: CX-9 Powertrain

• 
• 

Post in thread 'Mike's 2018 CX-9 Signature'

Feb 19, 2025

I just realized that I didn't update this thread regarding the rear diff. Here we go..

In January of 2024, I posted this thread regarding a clunking noise from the rear that I started hearing. It was determined that the rear differential was likely on its way out as the rear wheels would no longer engage (AWD stopped working).

In August of 2024, I drained the rear diff to confirm that it had failed. Grey, silvery fluid with chunks of metal came out. I tried contacting my dealer to request an out-of-warranty goodwill repair and was summarily dismissed, as I expected. It took...

• sm1ke

• 

I was able to get Mazda Canada to assist with the repair cost after some back and forth, and a lot of persistence and patience on my part. I think it helped that I never allowed my communication with them to get too "heated" - I tried to remain firm, logical and reasonable the whole time.

There is absolutely a management team or manager that these reps report to. The first time I asked for an escalation, I was also told that no manager would be able to help me. If its worth it to you, be persistent. If they say no, change your "angle" a little bit, explain your reasoning for wanting to speak to someone higher up the chain, and articulate your expectations with reasonable support.

For example, I made the case that Mazda set the expectation that the rear differential should last the lifetime of the vehicle, since there is no fluid change interval, only a visual inspection (that would not reflect any potential internal issues). When dealerships perform the inspection after an oil change, "rear differential fluid inspection" is not an item that is checked. As a result, customers are not expected to "maintain" the rear diff, so if it ever fails, it should not fall on the customer to repair/replace - it should then be considered a "premature" failure most likely related to a manufacturer defect.

Hope you can get some assistance with the repair.

 

[CrazyHippie]

I'd suggest to look for a rebuilt rear differential (readily available) and install it privately. I'd estimate an all-in cost around USD1500. I just had this very thing occur on a 2014 CRV, and Mazda uses very similar AWD technology.

 

[CrazyHippie]

Cx5 2017 manual does not list any service maintenence for fluid at any number of miles, only when vehicle is submerged, which it never was (CO and PA). Regular mazda dealership visits, and never once mentioned about rear differential oil replacement or issue until now. Why should the customer be responsible for Mazdas lack of accountability for proper maintenance. A cursory online search shows that it is an issue. The customer rep also did state it was an issue shes been getting calls about. The mazda dealership guy did admit that there was no maintenance details for this problem.

Remember - OEM maintenance recommendations are meant to get you to the end of the warranty, and no further. Its actually profitable if failures occur after warranty expiration. There is no such thing as 'lifetime' lubricants - they all break down. Changing brake fluid, transmission fluid, coolant, rear differential fluid, etc., is a good practice.

 

[wlong01]

Remember - OEM maintenance recommendations are meant to get you to the end of the warranty, and no further. Its actually profitable if failures occur after warranty expiration. There is no such thing as 'lifetime' lubricants - they all break down. Changing brake fluid, transmission fluid, coolant, rear differential fluid, etc., is a good practice.

Don't forget transfer case gear oil too.

 

[GFrosty]

For my 2016.5 CX-5 GT AWD, the Owners Manual indicates the following maintenance servicing for the differential:

*5 If the vehicle is operated primarily under any of the following conditions, replace the rear differential oil at every 48,000 km (30,000 miles).
a) Towing a trailer or using a car-top carrier
b) Driving in dusty, sandy or wet conditions
c) Extended periods of idling or low speed operation
d) Repeated short trips of less than 16 km (10 miles)

*6 If this component has been submerged in water, the oil should be replaced.
​

But, interestingly, the 2017 CX-5 only indicates the following ... for normal and severe driving conditions, for USA, Canada and Mexico:

* 5 If this component has been submerged in water, the oil should be replaced.
​

Took a look at the 2022 CX-5 manual as well. It, too, only indicates the "submerged in water" maintenance warning.

If out of warranty, I can see how Mazda might point to their maintenance specifications and not want to cover the repair.

My own 2016.5 is almost 10yrs old. At 135Kmi, it has had the transm/transf/diff fluids changed out twice, now, and this coming year will be done a third time. When I acquired the car (pre-owned), I noticed in the manuals the between "normal" and "severe" service Schedules for maintenance. Wanted to err on the side of caution. Particularly with so many CX-5 owners choosing to change the drive line fluids at 30-50Kmi intervals. Doesn't help with your 2017, I know.

 

[N7turbo]

c) Extended periods of idling or low speed operation

Not understanding this being a bad thing for a differential.

 

[n0m0remazda]

I have had to get my rear differential replaced at 113k kms (70k mi) on my 2018 CX-9. I tried to take really good care of that car, but I had not replaced the rear diff fluid when this all happened - although I don't think it would have made any difference. In my case, the car saw very, very little "offroading", just a short climb up a dirt road here and there. Never towed anything, and I never pushed the car hard in the snow. 95% city/highway driven.

I maintain that a rear diff failure is rare, but not unheard of. There have been a few cases reported on Reddit and Facebook, and 2 or 3 other cases mentioned here besides mine (2 other CX-9s and 2 CX-5s, including yours).

For reference:

2016~2023 Thread 'CX-9 Rear diff failure at 113k kms (70k mi)'

Dec 5, 2024

I'm posting this to vent, but also to inform.

Back in January, I noticed that the car started making loud clunking noises. They were coming from the rear and seemed to be intermittent at first, but I soon realized that I could only hear the sound when the traction control light turned on and AWD was supposed to engage. I contacted my dealership to book a diagnosis appointment, but they seemed very skeptical that this was an AWD issue and assured me that if there was an issue with the rear diff or the AWD system, I'd have a warning light on the dash (there are no warnings or lights...

• sm1ke
• Replies: 32
• Forum: CX-9 Powertrain

• 
• 

Post in thread 'Mike's 2018 CX-9 Signature'

Feb 19, 2025

I just realized that I didn't update this thread regarding the rear diff. Here we go..

In January of 2024, I posted this thread regarding a clunking noise from the rear that I started hearing. It was determined that the rear differential was likely on its way out as the rear wheels would no longer engage (AWD stopped working).

In August of 2024, I drained the rear diff to confirm that it had failed. Grey, silvery fluid with chunks of metal came out. I tried contacting my dealer to request an out-of-warranty goodwill repair and was summarily dismissed, as I expected. It took...

• sm1ke

• 

I was able to get Mazda Canada to assist with the repair cost after some back and forth, and a lot of persistence and patience on my part. I think it helped that I never allowed my communication with them to get too "heated" - I tried to remain firm, logical and reasonable the whole time.

There is absolutely a management team or manager that these reps report to. The first time I asked for an escalation, I was also told that no manager would be able to help me. If its worth it to you, be persistent. If they say no, change your "angle" a little bit, explain your reasoning for wanting to speak to someone higher up the chain, and articulate your expectations with reasonable support.

For example, I made the case that Mazda set the expectation that the rear differential should last the lifetime of the vehicle, since there is no fluid change interval, only a visual inspection (that would not reflect any potential internal issues). When dealerships perform the inspection after an oil change, "rear differential fluid inspection" is not an item that is checked. As a result, customers are not expected to "maintain" the rear diff, so if it ever fails, it should not fall on the customer to repair/replace - it should then be considered a "premature" failure most likely related to a manufacturer defect.

Hope you can get some assistance with the repair.

I did try to be civil about it, made the same case as you did, that it was expected to last the lifetime of the vehicle, and that there were no maintenance information in the cx5 2017 manual. Im not a car person so I take it to the dealership every so often, and I would expect that they'd tell me what to do in good faith to maintain the car.

As they have never suggested any changes to the rear differential oil, it now has "play" and needs to be replaced. Im not even asking for full coverage, just a "hey, we hear you, we understand, here's an X amount to help you out with the costs" from a billion dollar company. The mazda folks at the dealership were real quick to refer me to a sales rep (as the total cost of repair not including the differential came out to be about 8k), but just the indignity of the situation is turning me off. If this happens at less than 100k mile with no acknowledgement or accountability, why not go to honda or toyota, where these expensive issues are unheard of.

 

[n0m0remazda]

I'd suggest to look for a rebuilt rear differential (readily available) and install it privately. I'd estimate an all-in cost around USD1500. I just had this very thing occur on a 2014 CRV, and Mazda uses very similar AWD technology.

I was told to go to aamco and get a quote but its still paying thousands of dollars and I don't know if they have guarantees like a dealership would.

 

[n0m0remazda]

@n0m0remazda how many miles on your CX5 when the diff failed? Do you know if the fluid level was ever checked? Did you do any towing (boat, trailer, etc.) with it?

96k - they said it has a lot of "play" in it and could fail at any time. never towed, never submerged,

 

[sm1ke]

If this happens at less than 100k mile with no acknowledgement or accountability, why not go to honda or toyota, where these expensive issues are unheard of.

Unfortunately these types of issues plague every manufacturer, regardless of their reputation or past history. Some happen more often than others. Believe it or not, prior to the CX-90 and CX-70, Mazda as a brand ranks between Toyota and Honda when it comes to reliability. More recently, Honda is further down the list, and Mazda is usually very close to Toyota.

I recognize that this doesn't help your current situation. Ultimately it comes down to the person on the other side of the phone/computer screen that has the final say regarding coverage. Some people have been able to get full payment coverage with their reps, while others get nothing more than a "Sorry, here's a free oil change". So much of it depends on who you get on the phone and how far that person is willing to go, or how much you can wear them down.

I will say that a repair/replacement done at a 3rd party shop with used parts will be closer to the $2k-3k mark. Mazda quotes the repair high because they have high shop rates and they use brand new OEM components. In my case, my rear diff failed completely, but the most I would have paid without coverage would have been just over $6k CDN, and that includes labour and parts. I have no idea where they're coming up with $8k for yours. Also, with the replacement, I got a 1-year/12k km warranty on the repair through the dealer.

 

[madar]

As been said many times on here, no such thing as a lifetime fluid. ALL fluids should be changed at one time or another.

 

[n0m0remazda]

Unfortunately these types of issues plague every manufacturer, regardless of their reputation or past history. Some happen more often than others. Believe it or not, prior to the CX-90 and CX-70, Mazda as a brand ranks between Toyota and Honda when it comes to reliability. More recently, Honda is further down the list, and Mazda is usually very close to Toyota.

View attachment 379091

I recognize that this doesn't help your current situation. Ultimately it comes down to the person on the other side of the phone/computer screen that has the final say regarding coverage. Some people have been able to get full payment coverage with their reps, while others get nothing more than a "Sorry, here's a free oil change". So much of it depends on who you get on the phone and how far that person is willing to go, or how much you can wear them down.

I will say that a repair/replacement done at a 3rd party shop with used parts will be closer to the $2k-3k mark. Mazda quotes the repair high because they have high shop rates and they use brand new OEM components. In my case, my rear diff failed completely, but the most I would have paid without coverage would have been just over $6k CDN, and that includes labour and parts. I have no idea where they're coming up with $8k for yours. Also, with the replacement, I got a 1-year/12k km warranty on the repair through the deal

As been said many times on here, no such thing as a lifetime fluid. ALL fluids should be changed at one time or another.

Ya, as I obviously found out the hard way. Apparently, I can't trust the manufacuturer to release a car manual that has proper maintenance schedule. Nor should I trust my doctor to diagnose me correctly.