Differential or transfer case failure on the 2012 Mazda CX-9
When differential or transfer case failure gets reported
Owners of the 2012 Mazda CX-9 report differential or transfer case failure at a median of 55,000 miles. A quarter of the reports come in before 30,000 miles and a quarter after 60,000 miles, from 8 reports that carried an odometer reading.
A part like this is normally expected to survive 110,000 miles. It is the 6th most-reported problem on this model year.
The mileage distribution
The reported range runs from 30,000 miles at the tenth percentile to 70,000 miles at the ninetieth, a spread of 39,498 miles across the middle 80% of reports.
Reports bunched into a band this tight usually mean the component has a life of its own: it goes at roughly the same mileage regardless of who owns it.
38% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 28,764 miles | 32,316 miles | 52,527 miles | 58,000 miles | 68,262 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Putting it right typically runs $900–$4,200 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 7 model years of this car. It shows up earliest on the 2012, at a median of 55,000 miles, and latest on the 2007 at 135,000 miles.
By volume the 2011 carries the most reports, with 24; the 2012 has 10. A mode that appears across most years of a model is usually a design choice rather than a bad batch.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
Like one other incident, my complaint involves the transfer case which is specific to the AWD models. I was on a major roadway when I noticed a low, strange noise. About this time I was preparing to enter a turn lane when the car suddenly lurched and made an awful noise that literally sounded like the engine fell out. It then felt like I ran over said engine before the car came to an abrupt stop. Thankfully the light at the intersection had been red and traffic was slowing with me because I shudder at the thought if traffic had been moving at the regular rate of speed. Mazda roadside assistance had it towed to the dealership where the two guys immediately asked if it was an AWD model. They said that without even looking at it, based on what I'd said happened, they'd bet it was the transfer case. Thankfully the tc was still under the power train warranty, but it seems like mazda is aware of this issue. Would have seriously been nice to be alerted to such a potentially dangerous defect. I would have certainly had mine replaced to avoid being put into the situation I was in. *tr
While driving on interstate 90 west in massachusetts, 5 miles from route 84, our AWD cx-9 started making a very loud whining noise. Within 10 seconds, the car started bucking, making a grinding noise and the steering became difficult. I was able to maneuver to the left side of the road; I could not make it to the breakdown lane because of the car's condition. Once the car stopped, we smelled burning fluid and some smoke came out of the vents inside the car. The car was unable to drive on its own, the wheels seemed locked and the grinding noise was extremely loud when in drive or neutral. I had to call 911. The mass state highway patrol arrived and had to push us over to the breakdown lane while the car was in neutral. The the mass state police halted all traffic on the highway for this to occur. We sat in the breakdown lane for an hour waiting for a tow truck. This entire situation was very dangerous. I had a toddler in the car with us. The highway was only moving around 35-40 miles an hour and slowing at the time of the incident. The mass state highway patrol and tow truck driver stated that the car may have spun out or flipped…
While driving on interstate 90 west in massachusetts, 5 miles from route 84, our AWD cx-9 started making a very loud whining noise. Within 10 seconds, the car started bucking, making a grinding noise and the steering became difficult. I was able to maneuver to the left side of the road; I could not make it to the breakdown lane because of the car's condition. Once the car stopped, we smelled burning fluid and some smoke came out of the vents inside the car. The car was unable to drive on its own, the wheels seemed locked and the grinding noise was extremely loud when in drive or neutral. I had to call 911. The mass state highway patrol arrived and had to push us over to the breakdown lane while the car was in neutral. The the mass state police halted all traffic on the highway for this to occur. We sat in the breakdown lane for an hour waiting for a tow truck. This entire situation was very dangerous. I had a toddler in the car with us. The highway was only moving around 35-40 miles an hour and slowing at the time of the incident. The mass state highway patrol and tow truck driver stated that the car may have spun out or flipped…
Also reported on the 2012 Mazda CX-9
Other brake problem
Master cylinder or brake booster failure
Loss of braking
Airbag inflator rupture
Other engine problem
Other speed control problem
How far this goes
Complaints are voluntary, so 10 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does differential or transfer case failure happen on the 2012 Mazda CX-9?
Across 8 owner reports that included an odometer reading, half were filed by 55,000 miles. A quarter were filed before 30,000 miles and a quarter after 60,000 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is differential or transfer case failure on the 2012 Mazda CX-9?
10 reports have been filed with NHTSA, about 0.4 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed