CX-5 Diff, and how mine died like a dog.

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CX5 GT-R
My AWD light came on the other day, and my AWD was subsequently not working at all. A trip to the dealer resulted in the finding of several "weird" non-functional "gear ratio" codes (what I was told). A new diff was ordered from Mazda, and the entire rear diff was replaced. Upon failure analysis, it was decided that water incursion had caused the failure of the unit. This jives with what MikeM had opined about my crossing a road that had a creek that had risen, flowing over it. Water depth was between 6 and 10 inches, depending on the road surface, where I crossed (larger loose rocks). The moral of the story is that all of the "offroad" videos you have seen of the CX-5 in mud/water are NOT representative of the vehicle's capabilities, and you need to STAY OUT OF MUD OR WATER! If you do go into mud or water, GET THE FLUIDS CHANGED ASAP! WATER HAS MADE IT IN! The front diff fluid was also changed, and while dirty, showed no signs of water incursion. The transmission was not at risk because its vent-tube leads to near the battery. The rear diff is a $16XX unit, and labor nears $1K. Treat it like it's made of sugar, when you're around water! I have taken cars through much deeper water with no ill effect.

What IMPRESSED me was it took about a month to fail, and there were NO bearing noises, and nothing seized up. The fluid drained from it was putty gray, and looked terrible. I am very impressed with the bearings in that diff!!!


*SHORT VERSION FOR THE MENTALLY CHALLENGED*

--Diff breather ingested water when I crossed a road that had a risen creek flowing over it.
 
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2013 CX-5 6MT
thanks for the update.
Do you know what actually failed inside?

Since the diff wasn't making noise and wasn't seized up it must have been a part of the coupling component that failed.
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2016 CX-5 Sport AWD
As unfortunate as it is for this to happen to you with a brand new vehicle, I don't think one example good enough to determine the off-road capabilities of the vehicle.
 
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2014 QX70 AWD
As crappy as your situation is, I would be more than happy Mazda is replacing the unit free of charge. In the end, Customer Service trumps most everything else.
 
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CX5 GT-R
As crappy as your situation is, I would be more than happy Mazda is replacing the unit free of charge. In the end, Customer Service trumps most everything else.

I'm pretty pleased with the resolution, and am very pleased, mechanically (I mean, damn! It ruined the lubricant, and the diff still functioned without noise, albeit without AWD clutch capability. I am really impressed, actually), with all but how easily water entered the system. HOWEVER, crossing water is a dynamic event. Did the rear of the vehicle dip down? Did the speed of the stream hit some part of the undercarriage JUST right to crest and enter the diff? Who knows? Without a camera on it, I cannot tell. I CAN tell you that that one video with the CX-5 in the mud-pit ruined the diff unless the guy was SUPER lucky, but he will never know, as it was a press car and got turned in after the test. My diff took a month to fail...
 

MikeM.

MoMo
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2013 Mazda CX-5 Touring AWD 2.0L
Upon failure analysis, it was decided that water incursion had caused the failure of the unit. This jives with what MikeM had opined about my crossing a road that had a creek that had risen, flowing over it. Water depth was between 6 and 10 inches, depending on the road surface, where I crossed (larger loose rocks).

When crossing flood waters flowing across a road, with submerged rocks from flood debris, the suspension is going to be bouncing up/down. There may be portions of the roadway missing. This up/down action can create a pumping action with the water trapped under the vehicle, forcing it into places it shouldn't go (like the differential vent that all AWD and all 4x4 vehicles have). That is why the owner's manual for my 2013 AWD CX-5 says to drain and refill the differential oil anytime it has been submerged in water (pages 6-5 to 6/6 under "Maintenance and Care").

The CX-5 has class leading ground clearance and suspension travel but, like all vehicles, the ground clearance is measured with the vehicle unloaded and stationary. Driving over larger, loose rocks is doing to compress the suspension causing the water level to rise in relation to the body and creating a high pressure area of water under the vehicle with no where to go. This will happen on ANY vehicle. Even Jeep recommends replacing fluids of components that have been submerged. In your case, the actual failure was not caused by the water incursion itself, but because the water froze due to the fact that the flooding in NW Arkansas was immediately followed by an arctic air mass with temperatures low enough to freeze your differential solid overnight. Anyone putting a can/bottle of beer in a freezer overnight has witnessed the power of freezing water. Your failure is not surprising (I knew exactly what happened once you had described the environmental conditions preceding the failure). This is not a Mazda failure, it is a human failure to follow the very clear Maintenance instructions in your Owner's Manual. The fact that water entered the differential vent in the first place is not even slightly surprising given the depth of the water and the fact that you were driving over large, loose rocks submerged in the floodwater.

The moral of the story is that all of the "offroad" videos you have seen of the CX-5 in mud/water are NOT representative of the vehicle's capabilities, and you need to STAY OUT OF MUD OR WATER! If you do go into mud or water, GET THE FLUIDS CHANGED ASAP!

This is incorrect. I typically avoid water deep enough to submerge my differential because it ALWAYS entails a fluid change. This was true on my AWD Subaru and it was true on my very rugged and purpose built off-road Nissan Patrol 4x4. But all these vehicles are capable of making water crossings, just like the videos depict. The fact that all of these vehicles have this capability, does not imply that you do not need to do additional maintenance. And while some larger Jeeps, Nissans, Toyotas, etc. can ford deeper water without submerging the differential, you still need to drain and refill after submersion. My Nissan Patrol had a "water protect" distributor that protected the ignition system during deeper water crossings and an oil bath air filter with water drain that protected the intake air from water intrusion. It was designed to ford water deeper than the differential. But it still required a drain/refill afterwards. The main difference is it had much larger diameter tires and water that might submerge a CX-5 differential might not submerge the Patrol differential.

The videos depict real world capabilities that may come in handy in real life. But don't for a minute think that such duty doesn't entail additional maintenance responsibilities. Every experienced off-roader knows this and your Owner's Manual doesn't mince words either.


The rear diff is a $16XX unit, and labor nears $1K. Treat it like it's made of sugar, when you're around water!

No, don't treat it like sugar, just follow the clearly stated maintenance requirements. In fact, you are lucky Mazda is covering this under warranty because immediately preceding the requirement to drain/fill the differential after submersion is the following statement:

"To continue warranty eligibility and to protect your investment, it is your responsibility to properly maintain your vehicle according to factory recommended schedules contained in this manual."

The problem with this country is very few people want to take responsibility for their actions. They prefer to blame the manufacturer of a product rather than their own failings. The fact that your much bigger Jeep went through similar water is no excuse. Oh, wait, didn't your Jeep have similar expensive problems before you dumped it? Do you always ignore the maintenance schedule and them blame the manufacturer?

You should be praising Mazda for covering your irresponsibility and ignorance under warranty. And people wonder why cars cost so much! Partly because we all pay for repairs done under warranty, even when it is the owner's clear negligence that caused the failure! I don't expect you to admit this as you are always right and the manufacturer of these amazing offerings is always at fault. You will simply make up more excuses and squirm around the central issue here which is personal responsibility.
 
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2016 CX-5 Sport AWD
Well, be my guest in testing the theory ;)

Water in a differential won't cause it to fail very shortly there after. It won't last very long, but based on how you described it, the time between the water crossing and failure are minimal. I've had water in differentials in my off-road vehicles before from cracking the housing and driving through rivers, never had a failure ( I did change the fluid when I got home).

However, to extend the vent tube on a differential is a piece of cake, just get a longer proper size hose and run it somewhere where water cannot reach. That is what I did on my old jacked up Ranger. I ran the front diff vent up by the brake MC, and the rear by the fuel cap. On can easily do the same on a CX and do river crossings and then you won't have to stay out of mud/water as you stated.
 
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Chris_Top_Her

Banned
Moderator
Contributor
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San Antonio, Texas
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'15 CX-5 Miata AWD
Don't gotta be a butt about it. If anything it's more experience and knowledge added to the forum. The more you know. The best way to use then awd is in performance driving with mods.
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MikeM.

MoMo
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2013 Mazda CX-5 Touring AWD 2.0L
Don't gotta be a butt about it.

I didn't see anyone "being a butt about it".

In case you were referring tomy comments, I'll add that I'll call out anyone who blames the manufacturer for their own failure to follow the plainly stated Maintenance requirements. And this is especially true when those maintenance requirements are common to ALL AWD and 4WD vehicles. People need to take personal responsibility for their failings rather than try to publicly blame the manufacturer. To be clear, I'm not blaming Unob for sharing his experience, only for not taking personal responsibility for the damage. This will happen to any differential with water left to a hard freeze. And submerging any differential, even ones with owner modified snorkel extension breathers, will draw some water through the seals when a hot differential is submerged in cold water.

If that constitutes "being a butt" in your mind, so be it!
 

Chris_Top_Her

Banned
Moderator
Contributor
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San Antonio, Texas
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'15 CX-5 Miata AWD
I didn't see anyone "being a butt about it".

In case you were referring tomy comments, I'll add that I'll call out anyone who blames the manufacturer for their own failure to follow the plainly stated Maintenance requirements. And this is especially true when those maintenance requirements are common to ALL AWD and 4WD vehicles. People need to take personal responsibility for their failings rather than try to publicly blame the manufacturer. To be clear, I'm not blaming Unob for sharing his experience, only for not taking personal responsibility for the damage. This will happen to any differential with water left to a hard freeze. And submerging any differential, even ones with owner modified snorkel extension breathers, will draw some water through the seals when a hot differential is submerged in cold water.

If that constitutes "being a butt" in your mind, so be it!

For someone who shared a malfunction and the possible cause from the start, and the details of the process start to finish, I just don't see the need to have a seemingly "**** you for sharing because that's what you get attitude" lol. He could have easily left the fording bit out. Although really there was a lot of retarded arguing about it going on anyways.
 
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CX5 GT-R
I didn't see anyone "being a butt about it".

In case you were referring tomy comments, I'll add that I'll call out anyone who blames the manufacturer for their own failure to follow the plainly stated Maintenance requirements. And this is especially true when those maintenance requirements are common to ALL AWD and 4WD vehicles. People need to take personal responsibility for their failings rather than try to publicly blame the manufacturer. To be clear, I'm not blaming Unob for sharing his experience, only for not taking personal responsibility for the damage. This will happen to any differential with water left to a hard freeze. And submerging any differential, even ones with owner modified snorkel extension breathers, will draw some water through the seals when a hot differential is submerged in cold water.

If that constitutes "being a butt" in your mind, so be it!
As you will note, now that the failure mode is clear, I die NOT blame mazda. Quite the opposite. They would not have covered it, but the dealer failed to do due diligence before and during the repair, and thus they could not rightly charge me because the tech performed the work with me being told it was 100% covered. Dealerships will eat thay cost to retain customer loyalty in a case like this, which, they have. When I buy another vehicle, it will be from them if at all possible.

Also, the suction you speak of well could have done it. I had not thought if that, but it's very possible.

You will also note thay once failure was made clear, I did indeed say it was caused by lack of following procedure, because I did not know the procedure was required. My jeep had no issues with stuff like this because the breather tubes all ended in the engine bay. I never suspected mazda would put the breather so low. It was ignorance and failure to follow instructions, yes.
 
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Kedis82ZE8

'15 CX-5 GT AWD, '12 GX 460, '07 G35x
Contributor
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'15 CX-5 GT AWD
Any short term issues with plugging the vent tube on the diff? Say... just short term while off-roading? I haven't looked how easy it is to access though.
 
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2018 Tiguan SE AWD Mitsubishi Evolution 2003
Thanks for sharing . I will have to take a look down there in the spring time to maybe extend the breather tubing if I think it is necessary.