Should I have my transmission fluid changed?

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Nov 26, 2020
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2010 Mazda 3 2.0 no skyactiv. 125,000
I’m most likely getting rid of it next year, everything shifts great right now
I did have the fluid flushed at the dealer at 75,000. I was thinking one or two drain and fills? I really would hate for this thing to die before I sell it next year
Thanks
 
I had always thought that with drain/fills the conventional wisdom is it takes 3. The number on my car is that after 3, 19% of old fluid remains, where diminishing returns kicks in. 4th was something like 11%, etc. A drain and fill can never get to 0% old fluid, but we have to be practical.....on my car after 1 drain/fill, 51% old fluid remains

p.s. because the tech was willing to let me watch, and to set aside old fluid (Toyota trans), we compared...it was pretty black even when first was done at 82k, and after 2nd, and 3rd, believe it or not...with my wife's GM where I DIY'd, it was pretty pink after just 1 drain/fill and a full 5 qts came out, which is a lot....the toyota is < 3 quarts and closer to 2....that toyota 1 year later we did a 4th...he only charged me for #1, #2 and #3 one charg labor just double for fluid, then #4. So 2&3 were combined as he had the car all day and drove it some more...is it worth $360 for 4 of them? Not really sure but I'm ok with it....
 
Because you already did a fluid change at 75,000 miles, that relieves the notion/myth/idea that a first time change at high mileage might stir up gunk or otherwise muck up a transmission that was running o.k. otherwise.

I vote change the fluid. With the current situation, you may have to keep this car longer than you intend.
 
Every 50K-60K miles is a good rule of thumb for a step-shift automatic tranny.
One X D & F is good enough. You don't want to drain out too much clutch material all at once...It is said!
 
2010 Mazda 3 2.0 no skyactiv. 125,000
I’m most likely getting rid of it next year, everything shifts great right now
I did have the fluid flushed at the dealer at 75,000. I was thinking one or two drain and fills? I really would hate for this thing to die before I sell it next year
Thanks
If you are certain you will be selling it next year, had it serviced at 75k, I wouldn't change it.
 
The number on my car is that after 3, 19% of old fluid remains, where diminishing returns kicks in. 4th was something like 11%, etc. A drain and fill can never get to 0% old fluid, but we have to be practical.....on my car after 1 drain/fill, 51% old fluid remains
You're basing those numbers on those calculators for fluid replacement ? I think they are just a guideline and are strictly based on math, nothing else. I do use them too and on my cars, once I reach 70-75% "new", I increase the interval quite a bit. I do know that when I drain fluid, it still smells and looks really good so I'm content....

I've often wondered if someone with CFD (computational fluid dynamics) could model fluid changes. It would actually require the specific transmission too.
 
If you plan to keep it a while change it out.
It's easier than an oil change.
Fluid is not crazy expensive either.
 
If you plan to keep it a while change it out.
It's easier than an oil change.
Fluid is not crazy expensive either.
shop around, fluid is not as cheap as it used to be.......
Walmart.com usually has the lowest price and it will be on your front porch in a few days.
 
2010 Mazda 3 2.0 no skyactiv. 125,000
I’m most likely getting rid of it next year, everything shifts great right now
I did have the fluid flushed at the dealer at 75,000. I was thinking one or two drain and fills? I really would hate for this thing to die before I sell it next year
Thanks
If you're going to sell it no, unless you want to benefit the buyer. Only junk transmissions fail at 125k even with OE fills.
 
2010 Mazda 3 2.0 no skyactiv. 125,000
I’m most likely getting rid of it next year, everything shifts great right now
I did have the fluid flushed at the dealer at 75,000. I was thinking one or two drain and fills? I really would hate for this thing to die before I sell it next year
Thanks
Just do one drain and fill since you plan on selling it anyways . a little fresh additives would only help prolong the transmission life
 
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