Since they don't list it in the owner's manual, there's really no Mazda-speficied fluid change interval. The ATX in the 3 is known to be hard on fluid, so you won't want to go longer than 30-35k between flushes. I flush mine every 25k just to be safe.

 

Check the ATF color every now and then and observe the color. Red is the normal color. When it starts turning a dark brown, then it's time to change.

 

The Mazda-specific fluid is the same as Ford's Motorcraft fluids...which I believe is manufactured by Valvoline.

Regardless of the fluid brand, use Mercon V NOT M-V or equivalent...Motorcraft/Mazda, Valvoline, Castrol, Halvoline make it.

I would do you first oil change around 2000-3000 miles and then 5000 miles after that. I do the ATF every 25000 miles, whether it needs it or not but it has the past 2 times (I'm at 60k miles on my 2.3l 5-speed ATX).

 

[quote author=TEXNTHREE link=topic=154078.msg3299745#msg3299745 date=1251401924]
Regardless of the fluid brand, use Mercon V NOT M-V or equivalent...Motorcraft/Mazda, Valvoline, Castrol, Halvoline make it.
[/quote]

I think you have that backwards; Mazda recommends M5 (renamed from M-V to avoid confusion with Mercon V) for the 3's ATX. A number of synthetic ATFs, such as Mobil 1, are compatible with both Mercon V and M5.

 

You're right, I think I confused myself writing in haste. M-V is the same as FRN5, and is an equivalent to Mercon V.

FNR5 spec: http://www.fcsdchemicalsandlubricants.com/supplier/product.asp?product=FNR5%20Automatic%20Transmission%20Fluid&category=

So, to answer the original question: Mercon V, Mazda M5, Motorcraft FRN5 will all work just fine.

 

Yeah, Mazda will say that Mercon V isn't the same as M5, but in practice you won't notice a difference. Many folks here have flushed their ATX's with Mercon V with no ill effects. (I think you're right though, the formulations are very close.)

 

The only difference is Mercon V starts out a little bit thinner than M5 after a cold start. Which I feel is better as it helps cold start fuel economy and lessens pressures inside the AT. Once at operating temp they are basically the same. Viscosity is comparable to a 5w20 motor oil. Mercon V has a great additive package, as well as being semi-synthetic.

BTW I have done several drain and refills using Supertech Mercon V. I now do a 3.25 quart drain and refill every 10,000 miles. Keeps the fluid looking brand new.

 

Ive been hesitant to put the mercV in there because its not recommended but it seems many people are running it with no problems. Its a bit cheaper too.

 

[quote author=TEXNTHREE link=topic=154078.msg3300854#msg3300854 date=1251470049]
You're right, I think I confused myself writing in haste. M-V is the same as FRN5, and is an equivalent to Mercon V.

FNR5 spec: http://www.fcsdchemicalsandlubricants.com/supplier/product.asp?product=FNR5%20Automatic%20Transmission%20Fluid&category=

So, to answer the original question: Mercon V, Mazda M5, Motorcraft FRN5 will all work just fine.
[/quote]

The Mercon V spec, from the same site, says not to use where FNR5 (aka Mazda M5) is specified.

http://www.fcsdchemicalsandlubricants.com/main/product.asp?product=MERCON%AE%20V%20Automatic%20Transmission%20and%20Power%20Steering%20Fluid&category=Transmission%20Fluid

 

Well then, Lithia Ford service dept. has been telling me wrong for 4 years!

 

I've been wondering this for some time. I think it really depends on your driving behavior, and weather where you live.

wouldn't it be an indicator if the car wasn't shifting smoothly?

How much does mazda dealerships charge for a flush anyway?