Vague Transmission Oil Change Recs Vs Common Sense & Reality

While using non specified ATF is very unlikely to cause transmission damage, this transmission does seem to be quick sensitive to changes in transmission fluid viscosity (As it changes based on temperature)
yes it can... mazda even said so in dealer bulletins/newsletters years ago, and if they find any red fluid in a transmission that calls for the blue fluid, warranty voided
 
More than half the units we have had to overhaul have had non FZ fluid in them. Every one of them that had non FZ fluid had failed Low/Reverse clutch sets and damaged torque converter clutches (as well as other issues), its not normal to have pattern failure like that whereas none of the units with FZ have had those failures, the cylinder deactivation cars being the exception, the converter fails for other reasons. The normal failure modes have been the case bearing rotating or early valve body wear leading to pressure issues throughout the unit.
 
More than half the units we have had to overhaul have had non FZ fluid in them. Every one of them that had non FZ fluid had failed Low/Reverse clutch sets and damaged torque converter clutches (as well as other issues), its not normal to have pattern failure like that whereas none of the units with FZ have had those failures, the cylinder deactivation cars being the exception, the converter fails for other reasons. The normal failure modes have been the case bearing rotating or early valve body wear leading to pressure issues throughout the unit.
That’s quite telling with back of the napkin statistics. Leaving the transmission alone with the factory fill likely results in a lot less failures than servicing with non-FZ fluid. I imagine the majority of people aren’t touching the factory fill of transmission fluid, so to hear more than half of your overhauls have non-FZ fluid is crazy.
 
That’s quite telling with back of the napkin statistics. Leaving the transmission alone with the factory fill likely results in a lot less failures than servicing with non-FZ fluid. I imagine the majority of people aren’t touching the factory fill of transmission fluid, so to hear more than half of your overhauls have non-FZ fluid is crazy.
It really depends on the family how picky they can be on fluid. FZ does have a pretty particular additive package to allow correct torque converter release at low rpm. Clutches that are already together like to stay together. When the pressure releases on the TCC solenoid it drains that portion of the lube circuit, that happens very quickly but the clutches still want to hang together. The additive helps that release to happen smoothly and without shudder.

Coefficient of friction is part of what the actual friction material is made of and the fluid itself. There are three different materials used inside the Skyactiv. Some have a lot of graphitic material and some are more paper/cork style. The Low/Reverse are heavy graphite and the way the lube circuit in that section is designed is a little small. That allows good clamping and holding good pressure, if the fluid is too thick its not going to evacuate like it should and can also hang clutches up. Those type of clutches need good flow to remove the heat generated, they also make more heat. The steels will get hot spots on them and at that point its like a manual transmission flywheel where the clutch will just not grab correctly.
 
It really depends on the family how picky they can be on fluid. FZ does have a pretty particular additive package to allow correct torque converter release at low rpm. Clutches that are already together like to stay together. When the pressure releases on the TCC solenoid it drains that portion of the lube circuit, that happens very quickly but the clutches still want to hang together. The additive helps that release to happen smoothly and without shudder.

Coefficient of friction is part of what the actual friction material is made of and the fluid itself. There are three different materials used inside the Skyactiv. Some have a lot of graphitic material and some are more paper/cork style. The Low/Reverse are heavy graphite and the way the lube circuit in that section is designed is a little small. That allows good clamping and holding good pressure, if the fluid is too thick its not going to evacuate like it should and can also hang clutches up. Those type of clutches need good flow to remove the heat generated, they also make more heat. The steels will get hot spots on them and at that point its like a manual transmission flywheel where the clutch will just not grab correctly.
great info... I'm sure you know already that maxlife is on the thick side, so stubbornly calling the transmission whine "normal" and "still works fine after 30k miles" just makes me go "wow"... lol
 
Question, is there a special light or device that is used to identify the type of fluid drained from a transmission when it appears brown to the naked eye? The original fluid came out brown after 153K miles, and I could barely detect any red after the first drain/fill with Type M. When fresh, it was red like cranberry juice. After the next drain/fill with blue Aisin FZ, it was still brown. Or are there different shades of brown? Maybe I should have smeared some on a piece of paper towel. 🧐
 
Question, is there a special light or device that is used to identify the type of fluid drained from a transmission when it appears brown to the naked eye? The original fluid came out brown after 153K miles, and I could barely detect any red after the first drain/fill with Type M. When fresh, it was red like cranberry juice. After the next drain/fill with blue Aisin FZ, it was still brown. Or are there different shades of brown? Maybe I should have smeared some on a piece of paper towel. 🧐
This is a good question. My mechanic indicated that the previous mechanic who worked on the transmission may have used red fluid. Said the fluid which came out was brown. Transmission shifted great, but I noticed the occasional hard shift from 2-3 when cold. Doing a drain and fill actually helped alleviate most of it.

I'm at 337k km now and trans feels strong. The pan has been dropped 4x, and 2x drain/fills.

I've also experienced this very strange surge only on upshifts, only from gears 2-6. Resetting the transmission resolved this and has not come back.

However, I notice that if I try to reset the transmission (adapt reset procedure) and am not successful, the upshift surge from 2-6 returns, forcing me to keep trying until it is successful. Otherwise, transmission shifts fantastic even when I compared to a CX-5 with only 36k km on it.

@sinistriel@ please give me your thoughts.
 
Just want to add that when I started experiencing transmission problems in June, I immediately blamed the old fluids. It was after the first D/F that I found the shifting pattern reset steps on Youtube. That's when I realized that there was a software aspect of the problem, fluid being hardware. (The other street cars I own are manual so there was less to blame). My problem could have been mainly software, old oem fluids apparently is safe to keep.

Before the transmission started acting weird, I had an electrical problem in May, the car would stall out randomly while driving at low speeds. It would start back up and run ok enough for me to limp home. One of the fault codes was about a ECM/PCM relay. I started throwing darts in the dark by cleaning the terminals, changing the battery, and replacing a ROOM fuse. I wasn't able to identify which relay was responsible. I got lucky that the codes and symptoms went away at that point. It doesn't make sense.

Didn't think about the connection until now.
 
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Just want to add that when I started experiencing transmission problems in June, I immediately blamed the old fluids. It was after the first D/F that I found the shifting pattern reset steps on Youtube. That's when I realized that there was a software aspect of the problem, fluid being hardware. (The other street cars I own are manual so there was less to blame). My problem could have been mainly software, old oem fluids apparently is safe to keep.

Before the transmission started acting weird, I had an electrical problem in May, the car would stall out randomly while driving at low speeds. It would start back up and run ok enough for me to limp home. One of the fault codes was about a ECM/PCM relay. I started throwing darts in the dark by cleaning the terminals, changing the battery, and replacing a ROOM fuse. I wasn't able to identify which relay was responsible. I got lucky that the codes and symptoms went away at that point. It doesn't make sense.

Didn't think about the connection until now.
I was getting a P0600 code over this winter. My battery, though aging, apparently still held a normal voltage, but was probably failing under load. Replacing it with a new one got rid of that code and it never came back.

It's likely the new battery resolved your code
 
I was getting a P0600 code over this winter. My battery, though aging, apparently still held a normal voltage, but was probably failing under load. Replacing it with a new one got rid of that code and it never came back.

It's likely the new battery resolved your code
This is too high tech for me, weak battery throwing scary codes! 😭 Everything was fine before this though, nothing wrong with shifting. It's like saying my upset stomach is somehow related to my not wearing shades in the sun.
 

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This is too high tech for me, weak battery throwing scary codes! 😭 Everything was fine before this though, nothing wrong with shifting. It's like saying my upset stomach is somehow related to my not wearing shades in the sun.
Yep, that's likely to be a weak battery. When the voltage is weak, especially under load, it can mess around with communication.

How many years and KM on your OG battery?
 
Yep, that's likely to be a weak battery. When the voltage is weak, especially under load, it can mess around with communication.

How many years and KM on your OG battery?
OG was good from 2/2017 through 7/2023, with maybe 95K miles? Replaced it when it drained itself overnight and my jumper pack couldn't bring it back right away. I logged an oil/filter change in 10/2023 at 101.5K miles. The next one from AutoZone was replaced this May. I noticed that it was leaking with white powders around the terminals. I kept it for my backyard solar system and it is still leaking from the top caps. Sorry I didn't mean to derail the discussion. 😅
 
This is a good question. My mechanic indicated that the previous mechanic who worked on the transmission may have used red fluid. Said the fluid which came out was brown. Transmission shifted great, but I noticed the occasional hard shift from 2-3 when cold. Doing a drain and fill actually helped alleviate most of it.

I'm at 337k km now and trans feels strong. The pan has been dropped 4x, and 2x drain/fills.

I've also experienced this very strange surge only on upshifts, only from gears 2-6. Resetting the transmission resolved this and has not come back.

However, I notice that if I try to reset the transmission (adapt reset procedure) and am not successful, the upshift surge from 2-6 returns, forcing me to keep trying until it is successful. Otherwise, transmission shifts fantastic even when I compared to a CX-5 with only 36k km on it.

@sinistriel@ please give me your thoughts.
You've likely got some wear happening that the TCM has learned to compensate for. Part of the relearn procedure is relearning the touchpoint of each clutch set and that does change over time. The TCM is constantly monitoring that but sometimes it needs a little kick to really 'look' at it.

When you log the learn process it looks like this.
1755623401768.webp


That is each linear solenoid responsible for each clutch set minus the TCC solenoid which wont relearn until you start to drive it. For those that feel it in the brake pedal during the relearn what you are feeling is each solenoid moving the clutch sets to the touchpoint and then pulling back and rapidly cycling it.

If we look closer we can see what that looks like based on amperage command. For my personal car it takes .38 amps to bring my Low Clutch to its touchpoint. It brings it to the point, backs off a little then applies a full amp to give a full engagement.



1755623657663.webp
 

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