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Tranny Flush Vs Drop the pan + Change Filter

2013 Mazda 5
When I bought it 2 yrs ago with 85k it had the original (dark) oil
Dealer flushed it twice to get the color right.
Its been fine to date.

Wondering what should I do next time and when?
Is 60k about right? How often - 5yrs?

Should I not flush but Drop the pan and have the Filter Changed going forward?

Just what ever lets you sleep at night.

I let people read this, and then they can decide.

https://www.straighttalkautomotive.com/articles/transmission-flush.html

Tester

I have a pan drop/or drain & fill every 30,000 miles from new. My trans guy says a pan drop is normally all that is necessary if regularly maintained. Nothing wrong I guess with a full exchange unless the transmission is very dirty. Then other precautions need to be taken. So if it were me, after two flushes, I’d just do the pan drop and filter change. Question though why it was so bad after just 80K? Maybe hard usage or maybe just normal dark instead of filthy/worn out. Others will disagree.

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A replaceable filter should be changed; especially after the car accrues a few miles on it. Partial clogging of the screen can lead to fluid shortages which can cause shifting difficulties and/or unnoticed pressure problems in the clutch drums and so on.

My cousin found this out the hard way some years ago with his Pontiac.

I like this - but how often if you are not driving a lot?
But you mentioned 30K for pan drop instead of 60k - is it a bit too soon?
Also if you are not driving much, how often should you do it?

Incidentally, my Acura Integra manual says every 2 yrs - even though I drive 5k/yr, I do it myself - its cheap and easier than oil change ($20 total cost - Amz seems expensive at $11/qt) - drain and fill no pan drop. The filter is buried inside and not intended to be replaced. But Mazda fluid is twice as expensive ($15/qt on Amz) and gets a bit complicated for an average person to do the Tranny fluid. Where is the good balance 5yr/60k? Scotty on Youtube says 60k though.

All the more reason to do a flush.

How else are you going to keep the filter clean?

Tester

Seriously . . . ?!

There’s no way in ____ I’m removing the pan and NOT replacing the filter

How’s that . . . ?!

If you don’t remove the pan, you can’t see what’s going on in there . . .

What are you talking about . . . ?

The transmission has a removable pan, and the filter is easy to replace once the pan is off

Unless your trans does not have a dipstick, a fluid and filter service should be very straightforward

Mazda likes pushing the idea of “lifetime fluid”, but my experience with Mazda 3 was that at 68K miles it is quite worn. I had it replaced with synthetic equivalent from Valvoline, as triple drain/fill and it still costed me less than OEM, shifts became smoother and it drives great at around 100K now. I was not dropping pan or replacing filter, as it is indeed a mesh strainer, so I took my chances.

I do not know about 5, but on 3 it is no dipstick visible under the hood, but they do have it as a stubby 5-inch thing attached with a bolt where normal dipstick tube should have been. Still, it has min/max marks, it is only PITA to work with it from underneath.

You are correct if one is comfortable putting the pan back without leak - changing the gasket is not likely avoid leaks. Experts might use some sealant and know the right torque etc - I never done this so … I would seek a mechanic as this car would go on a freeway for 500miles at a time!

Flush vs drop the pan, the great debate.

Drop the pan, that advantage is that yo can replace the filter and clean out the pan. The disadvantage is that it leaves about half your old ATF in the transmission.

Flush, advantage it gets most of the fluid out, not all like they claim but most. Disadvantage, the bottom of the pan doesn’t get cleaned and the filter does not get replaced.

The reason that all the fluid does not get changed during a flush is that the pickup for ATF is in the center of the pan just above the filter. The ATF gets sucked through the filter, distributed through the transmission, then it goes through the cooler and back into the pan somewhere on the side. The fluid in the pan is getting continuously diluted with fresh, but it is not a positive flow where only old goes into body and freah goes into the pan and they never mix.

It’s kinda like when the kid pees in your pool. You can empty the pool and refill or you could stick a pump in one end and the hose in the other constantly diluting the polluted water with fresh. Which one do you want to swim in?

Before I go on, you really don’t need to replace 100% of the ATF to be effective. As long as you haven’t taken the transmission to the point of no return, periodically getting some fresh fluid with fresh additives will keep the transmission going for a long time. This can get into a long story in itself but for now, I’m saying that with routine maintenance, 100% is not necessary.

But if you really want it to be 100%, then the first thing is to drop the pan, clean it, replace or clean the filter then reinstall the pan and fill the transmission back up. If you have one of those transmission that doesn’t have a dipstick, then carefully measure what you drained out and put that much back in. Now disconnect the cooling line where it goes into the transmission, that is after the cooler, hook up the exchange (flush) machine and flush out the body of the transmission and the torque converter. Only fresh fluid is being drawn up into the valve body and only fresh fluid goes into the pan from the exchange machine. Once the expelled fluid turns the color of the fresh ATF, it is done, 100%.

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I really don’t know if a flush cleans the filter. I have never had a “Flush”. At 145k mikes I did a disconnect the line at the radiator, directed to a bucket and marked quart lines on the bucket. Poured 13 new quarts in as old quarts got pumped out. The fluid on the dipstick had not looked too bad but was definitely soiled while looking at it in the bucket. Still having some trans inconsistency at 165k miles, so had a shop drop the pan and do 6 new quarts, as that is all you can do by dropping the pan, and a new filter. At 198k still doing good.

Thanks for the explanation

And you make a good point . . . don’t exceed your comfort level

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Yeah, I wouldn’t think a flush would do anything as far as cleaning the filter. Unless they flush in reverse. And then whatever the filter had caught would be back flushed back through the transmission. Sounds kinda sketchy…

I think I’m with @keith but I’m beyond my level of competence. It’s just what I do. I used to change the Acura fluid myself. There is a drain plug but no dip stick. So I just measured what came out and put that back in. Reasonably easy. I can’t do it on this one though. I don’t know about any two year recommendation but all the dealer told me was doing the trans, differential, and transfer case at the same time so it’s that at 30K at the dealer. But I do about 12K a year on that anyway. The other car goes longer but I never worried about a time limit. No dipstick either so one of the jobs I always hated to do is now done in a shop.

If such a thing is easy to do, removing the pan, cleaning all the gunk off the bottom, and replacing the filter is a good idea. If your shop wants to use a flushing machine to flush and replenish the fluid w/fresh stuff after the pan drop and filter replacement, if done correctly that probably works better than just a simple drain and fill.

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