Which CX-9 do you have?
The first generation (TB) was built from 2006 to 2015, with a 3.5-litre V6 and then a 3.7-litre V6 and a 6-speed Aisin automatic. The second (TC) went into production in February 2016 with a 2.5-litre turbo four and a 6-speed Skyactiv-Drive automatic, and the CX-90 has since taken over.
It matters because they're different cars underneath. A V6 and a small turbo engine don't share a service list, so have the year handy.
Why a CX-9 battery can fool a multimeter
A CarsGuide reader's 2009 CX-9 wouldn't start after sitting for three months, even though the battery checked out. The answer was that a battery can show 12 volts with nothing asking anything of it, then collapse when the starter motor pulls on it. The real test is the voltage while the engine cranks.
Parked cars also drain slowly. The alarm and the clock keep drawing power, and a battery left flat long enough often won't come back even with a charger on it. If your CX-9 sits for weeks, a mechanic or auto electrician can tell you whether anything is drawing more than it should.
Mazda CX-9 transmission fluid and the transfer case
Keep two things apart here. The automatic has its own fluid, and on all-wheel-drive cars the transfer case (the small gearbox that sends drive to the rear wheels) has its own oil.
CarsGuide says Mazda didn't specify an oil change for the transfer case on the 2010 car, so it never made the routine service list. The oil can break down, and most workshops now suggest changing it around 60,000 km. Damage can spread to the spline shaft joining it to the transmission, and CarsGuide says that's happened with as little as 70,000 km on the car.
Mazda extended US warranty cover on 2009 to 2013 builds to nine years, tying the trouble to towing or low-grip driving heating the oil. CarsGuide warns that may not apply to Australian cars.
For the automatic's fluid, go by what your service book lists for that car, and have the mechanic show you the line. A mechanic should do the job, because the level and the fluid type both have to be right.
Have the driveline looked at if you notice
- A hot, burnt oil smell after towing or a long climb
- A clunk or shudder when moving off
- A new whine that rises and falls with road speed
- Oil on the driveway under the middle of the car
- Metal specks in oil that's been drained
Recalls and CX-9 servicing
TB-series CX-9s sold between 15 November 2006 and 30 April 2013 were part of a Takata airbag recall round in August 2017. If you've bought one second-hand, check the VIN (the car's ID number, on the rego papers) on vehiclerecalls.gov.au.
All combustion Mazdas here now share 12 months or 15,000 km, according to CarExpert in June 2026. Older CX-9 books can show less, so go by yours. An independent mechanic working to Mazda's schedule and specifications doesn't by itself void the new car warranty.
Tell us the year and what the CX-9 is doing. A local mechanic who specialises in your car.
Our take on a CX-9
Get the battery load-tested rather than swapped on a hunch. On a TB with all-wheel drive, ask when the transfer case oil was last changed. If nobody knows, that's your answer, and we'd have it done before the next towing trip. Ask for the old oil to be looked at when it comes out, because what's in it tells the mechanic plenty.