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Discussion Starter #1
So, I dropped my car off at the local dealer to have them fit it with a new set of tires and they called me back recommending a transmission fluid flush $160. I was told there was no recommended intreval, but that the fluid was looking dark. I'm not sure if fluid needs to be changed or if they are just trying to pad my bill. I did a quick google search on the subject and found this:

For optimum protection, change the fluid and filter every 30,000 miles (unless you have a new vehicle that is filled with Dexron III ATF which is supposed to be good for 100,000 miles).

I have 34K miles, so maybe it should be changed, then again, they say if I have this Dexron III AFT, then I'm good for 100K. The manual says little to nothing on the subject. Anyone have some insight, I've got to call them back soon!
Thanks!
 

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Do you have one of the earlier 2010's with the transmission cooler? Or one of the later builds without the transmission cooler?

With the transmission cooler, it should keep your fluid good until at least 60k-100k interval that dunston stated. Without the transmission cooler, 34k is just about right. My girlfriend's 2006 3's ATF was nearly black at around 35k, so I did a fluid drain and refill and added a transmission cooler.

All this also depends on your driving habits, do you push the car hard or do you take it easy on it? The harder you drive the car, the hotter the coolant and tranny fluid will get, decreasing the fluid life.

Also, our fluid is Mazda M-V, which is different from Mercon V.
 

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Is the transmission cooler in the earlier 2010s located behind the driver's side vent above the fog light (I think I can see it by looking through the opening)? I don't have a service manual.

I have a 2010 S Sport.
 

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Is the transmission cooler in the earlier 2010s located behind the driver's side vent above the fog light (I think I can see it by looking through the opening)? I don't have a service manual.

I have a 2010 S Sport.
I think that is the oil cooler. On my later build (don't know the date, but it's post 2010.5) I've followed some lines from the cooler back to the trans. I was surprised to see this configuration (a separate cooler rather than lines running through the radiator).

Hard to imagine that some cars were built without oil coolers (as alluded to above).

I wonder if the cooler is thermostatically controlled? I've read that the typical set-up, with the lines running through the radiator, can also actually work as an oil warmer during cold weather....

BTW - I just learned that the Workshop Manual has finally been published - I'll pick it up in a few weeks and we can have answers to some of these questions :thumbup:
 

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Is the transmission cooler in the earlier 2010s located behind the driver's side vent above the fog light (I think I can see it by looking through the opening)? I don't have a service manual.

I have a 2010 S Sport.
I may have misspoke about the newer 2010's or above not having a transmission cooler for the automatics, I thought I saw that it was posted that they were removed, but I may be wrong on that. So, if you have the vent above the fog light and the cooler there, then your fluid being dark/black already might be due to your driving style. Have you looked at the fluid yourself? Does it smell burnt, or does it still smell sweet?

I wonder if the cooler is thermostatically controlled? I've read that the typical set-up, with the lines running through the radiator, can also actually work as an oil warmer during cold weather....
As far as the transmission cooler being thermostatically controlled, it is not. It is in-line with the "tuna can" cooler (which has coolant running through it), so that the oil is warmed before it is cooled. This results in no over-cooling and warming of the fluid in colder weather. It's basically the way many people have added transmission coolers to previous model year 3's.
 

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Discussion Starter #7
Yes, I have one of the early ones with the the cooler in the drivers front wheel well. Is it an oil cooler or ATF? Regardless, I was under the gun, and every other post I saw when I googled said changes should happen between 30-40k. I hated to do it, because I just bought a new set of tires, but I gave in and paid the price for the flush! :sad 1:
 

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It is an ATF cooler. There's nothing wrong with changing it early, if it does look like it needs to be changed. Next time, I would verify it though, rather than just taking the dealer's word for it. Dark brownish color is a sign that your fluid is getting too hot and burning up.
 

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Discussion Starter #9
It is an ATF cooler. There's nothing wrong with changing it early, if it does look like it needs to be changed. Next time, I would verify it though, rather than just taking the dealer's word for it. Dark brownish color is a sign that your fluid is getting too hot and burning up.
For future reference, how would you recommend verifying it at the dealer? Maybe you mean checking it myself beforehand?
 

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Just ask them to see the fluid yourself, or tell them you don't know what bad fluid looks like, so you'd like to see it.

I like to check my fluid every now and then, so that I know exactly how its doing.
 

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Discussion Starter #11
Just ask them to see the fluid yourself, or tell them you don't know what bad fluid looks like, so you'd like to see it.

I like to check my fluid every now and then, so that I know exactly how its doing.
Actually I did do that, but I was at work at the time. So when I picked it up and saw the fluid sample, who knows where it might have come from! Then again, I supposed to can't hurt to err on the side of caution when it comes to taking care of my Baby! :yes:
 

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I stopped taking mine to the dealer, their prices are ridiculously high, any good local shop would a perfect job for a fraction of the price
 
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