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What fluid to use for transmission flush?

Gibson486

Lifer
Getting ready to do a tran. flush on my Mazda 3 again. First time, it was done by the dealership. I suppose they used OEM fluid. The fluid they use does not last that long. It only lasted 20K the first time (it was all brown and yucky). Looks like it is time for another flush....At $12 a qt, I think I will avoid the Mazda brand fluid.

What would you recommend for M-V fluid (not the same as Mecron-V)? SO far, all I see is mobile 1 and Amsoil. They are both about $8 a qt. Any other company I should consider?


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Those 2 are fine, also Red line or Royal Purple. But I would check on your specific car on a Mazda forum to see if anyone reports issues with a specific brand in their tranny, or better results over another. I know RP has been known to eat through some kind of paper rings or something in my tranny, unless it's been rebuilt with carbon ones.
 
I'm not sure flushing your transmission is a good idea.

Or are you just replacing the fluid? The stuff is supposed to last a lot longer than 20k.
 
Why are you flushing your transmission? As stated above, you don't flush your tranny every 20k miles. The transmission in my moms 740i has never been flushed, only drained and refilled once and it has 150k miles.
 
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It's a Mazda 3. Go to a mazda 3 forum. Read up. It's a common complaint with the car. The stock fluid lasted 20K. The replacement fluid lasted 40K, although it has been brown for the past 10K.
 
I wouldn't spend $8/qt on transmission fluid for an economy car. But it can't hurt to try them and see how long they last.

If this is all over the Mazda 3 forums, what fluid have they been using and with what results?
 
I wouldn't spend $8/qt on transmission fluid for an economy car. But it can't hurt to try them and see how long they last.

If this is all over the Mazda 3 forums, what fluid have they been using and with what results?

No one really mentions what they use.....

Lots used Mecron-V, but then Mazda released a TSB to not use Mecron-V. Some mentioned mobile 1, but no one ever posts their results with it.....lots used the fluid straight from Mazda, but they complain that it does not last long at all....
 
Seriously. If that's the kind of quality you get from a Mazda, trade it in and get something else.
Other companies, even Dodge can make transmissions that go 100K miles without needing anything done to them.
There is a defect in that transmission, Mazda just doesn't want to address it.
 
Seriously. If that's the kind of quality you get from a Mazda, trade it in and get something else.
Other companies, even Dodge can make transmissions that go 100K miles without needing anything done to them.
There is a defect in that transmission, Mazda just doesn't want to address it.

LOL...that is what I thought....

but everyone (including some here) just tells me "oh, it's normal maintenance, just deal with it".

I just i finished paying this car off....it's like there is some big balloon payment at the end.

If I did not pay this car off, I would have have traded it in for another car....
 
I know GM will say mine is fine for 100k or even lifetime, but why risk damage, or faster wear, when it takes $50 and an hour or two every couple years + if you do your own maintenance?
 
Yes you would just be mixing the new in with the old. However you're replacing more than half the fluid that's been cooked with fresh fluid. The reason everyone is saying don't flush a tranny is that if you're going to do a flush, you run the risk of trash in the pan getting pushed back into the transmission. If you've ever dropped a transmission pan, after you drain the fluid off you'll see metal shavings collect in the pan. The transmission filter prevents them from being picked back up and circulated into the transmission. Doing a flush however can force that stuff back into the transmission.

For as complete a replacement of fluid as possible, you really need to drain it, drop the pan, clean out all the shavings, replace the transmission filter then put it back together and refill it. On the newer front wheel drive cars this can be a major chore as most times the cross member/engine cradle are in the way. You have to drop the whole cradle to drop the transmission pan. Major labor and can easily mess things up if you don't have the proper tools to align the cradle when you put it back on(depending on the car).

For your purposes a drain and refill is the best you can do without breaking the bank. You could also retrofit a transmission cooler to help keep the transmission oil temp down and prevent cooking your fluid as quickly. This is a solution many have used on the Honda's with transmission problems like this.
 
I never understood this....wouldn't you just be mixing the old fluid with the new?


Yea but you get enough out to refresh the old in their to make it last.

No you don;t get it all but you get enough to keep it working well.
I had to do a lot of Tran servies to FWD V6 GM cars from the lat 80's to Mid 90's as they put a heavy load on the trans and its fluid. I got about 200k out of a 3.8L FWD GM car that was known to have trans rarley make it to 100k. Some dodge vans have been known to have trans issues but just doing a pan drop helped a lot, of course so did adding a trans cooler.

I added a drain plug to a car of a pizza driver so he could do drain and fills every 10k. I think he was a little over 200k before the timing chain broke on it.
 
hmmm...well I called the mazda dealer....I asked about a transmission filter...they said Mazda told them not to touch the filter....maybe it's a sign that a drain and fill is what I should do?

How is a drain and refill different than the flush? Do you just drain 3 qts, put 3 qts, drive around the block and repeat?

Also, when you go to a vendor's (such as amsoil) website, they tell you to drop the pan and actually clean it the stuff from the magnets.....do you still do that in a drain and refill?
 
All you have to do (if you maintain your car regularly and properly) is open the drain plug, let it drain and drip for a while til its not dripping much anymore. Put the plug back in, put in a few quarts and if you have to check your trans fluid while running, start the car and check, adding until topped off. There should be a cold full line, and a hot full line. I checked both last time I did a drain+fill on an AT transmission.
 
If you have never replaced the filter I would do it. You can get a filter and gasket set from rockauto for $20. Drop the pan, clean pan out, replace filter/gasket, and then install pan and add fluid.

Use a Syn this time when you do it and see how long it last.
 
If you have never replaced the filter I would do it. You can get a filter and gasket set from rockauto for $20. Drop the pan, clean pan out, replace filter/gasket, and then install pan and add fluid.

Use a Syn this time when you do it and see how long it last.

should I ignore what the mazda dealer says then and just change the filter?

Also, how do you monitor how much liquid come out vs how much I put in? DO I just get a pan with measurements on the side?
 
Yea, a new filter is not going to hurt and I would replace at least at the first 60k mark and then anywhere from 30-60k after that based on need.


Does your car have a dipstick for the trans fluid? If so that is how you fill it. If it is sealed, or a pain in the ass like my Corvette, then read up on the method to fill after changing the filter/pan gasket.
 
Hmm, I was contemplating bring my Fusion in for a transmission flush soon (just over 40k miles), but reading the testimony about metal particles recirculating through the system + the $100-150 dealer fee has me thinking. Maybe I'll just do a drain and refill like you guys recommend - after all, if I want to get 90% of the old fluid out, I can just do another drain and refill a week later and eat the cost of more fluid, right?

IIRC, the manual says nothing about transmission service, just oil changes.
 
Hmm, I was contemplating bring my Fusion in for a transmission flush soon (just over 40k miles), but reading the testimony about metal particles recirculating through the system + the $100-150 dealer fee has me thinking. Maybe I'll just do a drain and refill like you guys recommend - after all, if I want to get 90% of the old fluid out, I can just do another drain and refill a week later and eat the cost of more fluid, right?

IIRC, the manual says nothing about transmission service, just oil changes.

I was doing research on it this last night....

I think flushing is not that big of a deal any more. In the past, a flush machine would send pressure though out the system. Today's flush machines are low pressure. I think both suck fluid out, but there are some systems that push it. The problem is you do not know which shop use the older machines, which are high pressure and can loosen the stuff.

The way I was going to do it was to disconnect the line and flush with the transmission's own pump. Drain and refill...I would do that, but since I am going to replace the filter, I am just gonna do the whole nine yards.
 
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