owner's manual is a good place to start

 

Never, according to Mazda. 50-60K miles according to common sense. Do a drain and fill, not a flush. Type is FZ. Capacity is 8.2 quarts.

 

Many folks suggest staying with the Mazda-branded type FZ. I agree. Forget about using a "universal" fluid. 100% re drain and drop versus flush. I advocate a trans filter change, pan/magnet clean, and while ur there check valve body torque with an inch lbs (or metric equiv) 1/4" drive (low range) torque wrench. Also, mandatory use of a torque wrench to reinstall the pan bolts!

 

It is a lifetime fluid. However, if you research the FZ fluid that the Mazda 3 transmission uses you will find out that it lasts 120k miles under normal operating conditions. So, I would change it around 100k-120k miles.

 

How long it lasts... that's a strange way of putting it. From day 1, wear particles from the clutch-pack, the steels, the bands, the drums, and friction materials from the lock-up clutch on the torque converter get generated. The ATF filter is not a bypass filter with tight filter media, but rather, is a quite coarse media through-filter. It would become occluded if it were tight-media. The generation-rate of wear particles in the ATF is totally contingent on:

• type of driving done (city, expressway, etc); and
• relative vigour with which the car is used (jack-rabbit starts or driving like Grandma).

Beyond wear particles generated, ATF life is impacted by the ambient conditions, the load the car pulls (affects slippage of torque converter and consequently heat produced), and the effectiveness of the ATF cooler. That heat can chemically change the ATF. Also, the degree to which gears and rolling element bearings shear the ATF - that lessens it's viscosity. Lower viscosity than spec'd by the designers can cause more wear.

Wear particles circulating hasten the wear of the steel pistons in the aluminum valve body, wearing it out sooner. Said wear particles also wear out rolling element bearings sooner.

There's no such thing as 100-120 k miles' life for ATF. With all of the bad things happening, 50k to 60k miles is reasonable... Sooner - better yet!

 

Thanks for asking this question!

 

I would definitely change it more often than every 120k miles.

 

I got over 200k on the original fluid. Drain and filled it with Amsoil stuff. Still running perfect.

 

Just drained and refilled? (i.e. you didn’t remove the pan or replace the filter)