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When to change transmission fluid

I have a 2008 Mazda 3 Touring with 38,000 miles on it. I noticed that the fluid on the dipstick was a little brownish. The owner’s manual says nothing about servicing the transmission. My local Mazda dealership said fluid should be pink; that brownish color was evidence it needed to me flushed and refilled every 36,000 miles. However, a local transmission shop with an excellent reputation, said my particular Mazda3 has a synthetic transmission fluid which is brownish in color and does not have to be changed for 100,000 miles. What do I do? Who’s right?

Auto transmission fluid should be changed every 30k miles and this means that if the transmission has a pan then the pan should be dropped, cleaned, and the filter changed.
In a case like this you do NOT have a flush only.

I don’t know much about what particular fluid the Mazda3 uses but generally speaking brownish fluid can point to a transmission problem; as in being discolored due to friction material and burned fluid.

To be honest, since the independent transmission shop stated the fluid does not have to be changed for 100k miles I’d avoid them.

If the manual says nothing about servicing the trans., then I would go with the shop’s recommendation. I would probably still not wait for 100k however.

Buy a bottle of Mazda transmission fluid and see if it is red or brown. Then go to a good shop and get it changed.

You don’t need a flush. A fluid change should run $50-60, less if it has a drain plug. The filter on these doesn’t need to be serviced every time. So, $50 for a fluid change every 30k or $3000 for a transmission every 100k or so.