2017~2025 CX-5 Rear Differential Failure

[cz5gt]

mine were not tight too except the front drain one.

torque spec seems 32-39 rear and 34-42 front. I put them at 34 rear and front at 37-38 ftlbs

 

[a69mach1377]

That 23mm socket will be in my tool box soon, jadmt!

 

[AL Cx5]

North Dakota is pretty cool when it comes to getting good gas. I don't change my air filter every other oil change (that would be about every 7000-8000 miles) but change it often.
View attachment 382208View attachment 382209

I'd like some of that 111 please! Then get a tune. I bet the tuner would dial in more timing!!!

Easy way to check, kinda old school. Ive see this method on Bo cats and track hoes. I have a spread sheet with part numbers, costs and such.

 

[philljazz]

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

I had my rear differential replaced in 11/2025 for $4500. The same noise occurred and yesterday my dealer (John Kennedy, PA) claimed it was caused by water damage, and therefore MY FAULT (even though I had nothing to do with the design of the Mazda 3, and do not drive through ponds.) "Meranda" - the same customer service rep referenced above sided with the Service Manager. I demanded written documentation of where the water damage occurred, and will provide my story to the BBB and PA Attorney General's office. I suspect I'll have to seek out a local mechanic and hopefully find a used part. I do want Mazda to feel pain over this.

 

[nickswhip24]

I had my rear differential replaced in 11/2025 for $4500. The same noise occurred and yesterday my dealer (John Kennedy, PA) claimed it was caused by water damage, and therefore MY FAULT (even though I had nothing to do with the design of the Mazda 3, and do not drive through ponds.) "Meranda" - the same customer service rep referenced above sided with the Service Manager. I demanded written documentation of where the water damage occurred, and will provide my story to the BBB and PA Attorney General's office. I suspect I'll have to seek out a local mechanic and hopefully find a used part. I do want Mazda to feel pain over this.

what,not even a year.......did they have any fluid in it....are your tires the same size.....something very very wrong....stop talking to the dealer and contact corporate...

 

[Kedis82ZE8]

Anyone know where the diff vent terminates in the rear area of a 3 AWD? I wonder if there is a rare issue with a car wash that allows water in like the ‘13-‘16.5 CX-5 models?

Reference

K

2013~2016 Post in thread 'CX-5 Rear Diff and Transfer Case Fluid Change: Tools, Parts and Links'

Dec 5, 2021

I've ordered the replacement diff breather/vent hose mentioned in TSB to address that potential problem

https://static.nhtsa.gov/odi/tsbs/2016/MC-10186908-9999.pdf

KE02-27-090

Wonder if that is what caused Unobtanium's rear diff failure years ago?

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

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...

mazdas247.com

• Kedis82ZE8

• 

 

[N7turbo]

Anyone know where the diff vent terminates in the rear area of a 3 AWD? I wonder if there is a rare issue with a car wash that allows water in like the ‘13-‘16.5 CX-5 models?

Great. I do an underbody spray a few times a year, mostly as we're coming out of winter. Hope I never have this issue.

 

[AL Cx5]

Anyone know where the diff vent terminates in the rear area of a 3 AWD? I wonder if there is a rare issue with a car wash that allows water in like the ‘13-‘16.5 CX-5 models?

Reference

K

2013~2016 Post in thread 'CX-5 Rear Diff and Transfer Case Fluid Change: Tools, Parts and Links'

Dec 5, 2021

I've ordered the replacement diff breather/vent hose mentioned in TSB to address that potential problem

https://static.nhtsa.gov/odi/tsbs/2016/MC-10186908-9999.pdf

KE02-27-090

Wonder if that is what caused Unobtanium's rear diff failure years ago?

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

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...

mazdas247.com

• Kedis82ZE8

• 

Has anyone been told or found water in their differential?

Have folks checked the diff level and changed the fluid on 30,000 mile increments?

I see a class action lawsuit with Mazda over their lack of providing a maintenance schedule and some differentials come from Mazda low on fluid.....

Mazda has the same physics as others. Lips seals let fine dust in that act as an abrasive. Their overpriced diff fluid is not magical.

Next time I'm under my CX5 I'll look for one. I've personally lowered the rear cradle assembly and didn't see a vent. Is the 3 diff that much different from a 5?

The Domestic IRS rear differential I changed out didn't have a vent hose either. My 2500 truck differential doesn't have a vent hose nor my Dana 60 tank of a diff in my drag car...

 

[jadmt]

Has anyone been told or found water in their differential?

Have folks checked the diff level and changed the fluid on 30,000 mile increments?

I see a class action lawsuit with Mazda over their lack of providing a maintenance schedule and some differentials come from Mazda low on fluid.....

Mazda has the same physics as others. Lips seals let fine dust in that act as an abrasive. Their overpriced diff fluid is not magical.

Next time I'm under my CX5 I'll look for one. I've personally lowered the rear cradle assembly and didn't see a vent. Is the 3 diff that much different from a 5?

The Domestic IRS rear differential I changed out didn't have a vent hose either. My 2500 truck differential doesn't have a vent hose nor my Dana 60 tank of a diff in my drag car...

there is a vent line on the top I do not know where it terminates at. it is a very small line.

 

[Kedis82ZE8]

Probably terminates in similar areas as the ‘13-‘16.5 models.

Former member hear with a ‘14 CX-5 IIRC… lost his diff from water intrusion.. TSB was unknown at that time years back.. he thought a water crossing but I think it was from a car wash

I change my front transfer and rear diff on 30k mile intervals.

 

[Kedis82ZE8]

Diff hose I used on mine shows as compatible to at least ‘25 CX-5

https://www.oemvehicleparts.com/oem-parts/mazda-differential-vent-hose-ke0227090a

 

[BoomerZoomr]

I doubt it’s what Mazda uses, but I have seen these small vents that screw directly into an axle or gearbox. No hose needed. That little cap on top fits loosely, but doesn’t come off.

 

[AL Cx5]

Diff hose I used on mine shows as compatible to at least ‘25 CX-5

https://www.oemvehicleparts.com/oem-parts/mazda-differential-vent-hose-ke0227090a

I may have forgot it was on our 24.

Ours hasn't been through a car wash yet.

I had a car throw a code from a car wash once. Some cars transmission fill tube leaked water into the trans and killed it from car washes. I guess we should be happy that Mazda put the trans dip stick and fill port under the air filter box....ugh

Gee, it would take a lot of under spray nozzles to get water into the differential.

If one is worried, remove the diff drain plug very slowly and let some liquid leak into a pan. If it's not water all is well. Do this after it has not moved for at least 24 hours. Quick and easy test on the rear differential for water.

I've changed 2 CX5 front and rear diffs and didn't see any water come out.

I do this water test on my methanol burning race engine. Methanol is famous for washing down the cylinders and attracting water. We let the car sit a day or two and remove the plug for a second and put back in. If water comes out, let it drain until we see oil, which is rare.

Aside, our NA methanol race engine runs at 5.1 air to fuel ratio, NA gas burner street car runs at 14.7:1. We are burning almost 3xs as much methanol than a street NA gas burner. One little upset say of an injector and a cylinder is washed down with methanol.

One more reason to change the differential fluid every 30k or sooner...

 

[nickswhip24]

I may have forgot it was on our 24.

Ours hasn't been through a car wash yet.

I had a car throw a code from a car wash once. Some cars transmission fill tube leaked water into the trans and killed it from car washes. I guess we should be happy that Mazda put the trans dip stick and fill port under the air filter box....ugh

Gee, it would take a lot of under spray nozzles to get water into the differential.

If one is worried, remove the diff drain plug very slowly and let some liquid leak into a pan. If it's not water all is well. Do this after it has not moved for at least 24 hours. Quick and easy test on the rear differential for water.

I've changed 2 CX5 front and rear diffs and didn't see any water come out.

I do this water test on my methanol burning race engine. Methanol is famous for washing down the cylinders and attracting water. We let the car sit a day or two and remove the plug for a second and put back in. If water comes out, let it drain until we see oil, which is rare.

Aside, our NA methanol race engine runs at 5.1 air to fuel ratio, NA gas burner street car runs at 14.7:1. We are burning almost 3xs as much methanol than a street NA gas burner. One little upset say of an injector and a cylinder is washed down with methanol.

One more reason to change the differential fluid every 30k or sooner...

i traced the rear diff. vent ,it looked similar to kedis82ze8 post above,the front i dont know yet....but i see a transmission vent hose in engine bay

 

[jadmt]

Has anyone been told or found water in their differential?

Have folks checked the diff level and changed the fluid on 30,000 mile increments?

I see a class action lawsuit with Mazda over their lack of providing a maintenance schedule and some differentials come from Mazda low on fluid.....

Mazda has the same physics as others. Lips seals let fine dust in that act as an abrasive. Their overpriced diff fluid is not magical.

Next time I'm under my CX5 I'll look for one. I've personally lowered the rear cradle assembly and didn't see a vent. Is the 3 diff that much different from a 5?

The Domestic IRS rear differential I changed out didn't have a vent hose either. My 2500 truck differential doesn't have a vent hose nor my Dana 60 tank of a diff in my drag car...

are you postitive? my ram 2500 does and seems like you would be blowing seals without it able to vent. it should be on the axle tube.

 

[Kedis82ZE8]

21-5C1 in this schematic is reportedly the breather tube for AT

https://www.zoomzoomnationparts.com/p/Mazda__CX-5/BREATHER-PIPE--BREATHER/105422307/FZ11215C1.html

 

[Kedis82ZE8]

The one in the trunk area is the intake. The exhaust vent for the diff is on the top of diff . I ordered one of these back in 2016 to confirm it was an exhaust only diff valve using some vacuum tests. On the top of rear diff somewhere.. think I located it in the day but can't remember now. It was from this thread but pics and links broken now.

R

Thread 'AWD Experience'

May 12, 2016

I will seldom drive my CX-5 off road, and seldom will again. But last week I avoided a 1 hour delay by turning out of a dead-stop traffic jam several miles long and driving through a deep ditch to a parallel road with zero traffic. Three 4wd vehicles did this before I tried it. 2 breezed through while the third got stuck and had to back out and try twice more before he got the right line. The CX-5 scooted through without wheel spin. That's the kind of performance that puts a smile on your face.

• Rarebit
• Replies: 29
• Forum: CX-5 Ownership & Lifestyle

PN: B39M26060

#9 in schematic

Rear suspension. Axle & differential.. 2017 Mazda CX-5 - CHARLOTTE NC - North Carolina

2017 Mazda CX-5 Rear suspension. Axle & differential. AWD.

www.onlinemazdaparts.com