Guide: ATF Drain/Fill

[yrwei52]

Did you have a leak? I'm not sure why ATF would ever need to be added.

It has been verified many times the factory fill on ATF is low. So as the rear differential gear lube. In my case and from many others the engine oil was low from factory too. The only fluid from factory which wasn’t low is the gear lube in front transfer case.

 

[N7turbo]

I see. My engine oil was over by 0.7 qts. In fact, many people got overfilled engines.

 

[Kedis82ZE8]

I see. My engine oil was over by 0.7 qts. In fact, many people got overfilled engines.

Was it measuring at the top level on the dipstick? Or above F? If I go by factory fill quantity on mine it gives me a fill halfway from L to F on the dipstick

 

[N7turbo]

Was it measuring at the top level on the dipstick? Or above F? If I go by factory fill quantity on mine it gives me a fill halfway from L to F on the dipstick

At my first oil change, I drained 5.8 quarts and refilled with 5.1.

 

[murky]

Measured with the engine running and at a certain temperature.

 

[yieldchase]

Your ATF was warm when you checked it, correct?

Yep and car level

 

[yrwei52]

I see. My engine oil was over by 0.7 qts. In fact, many people got overfilled engines.

I believe your Mazda dealer topped off the engine oil during new car inspection as that’s very easy to do. The same on engine coolant. I picked up my 2016 CX-5 right after it was unloaded from truck and I watched the tech doing the new car inspection tearing those protection films off as I special ordered my car. He wanted topping off the engine oil and coolant with some unknown oil and coolant (looks like tap water) sitting on his bench since both were low. I stopped him doing that and said I’ll top off these 2 fluids by myself, got Mazda moly oil and FL-22 coolant right from parts department and did it at home.

I actually checked the oil level on a couple of brand new CX-5’s at the time and they all at the same level like mine, a bit over a half between ADD and FULL marks on the dipstick. That made me feel batter that the low oil level on my brand new CX-5 isn’t unique.

We all know oil change overfill is almost a norm by the car dealers for some reason. And I believe your engine oil and many others were also overfilled during the new car inspection.

 

[yrwei52]

Yep and car level

When measure the ATF level, the ATF temp is at 50°C / 122°F when the car is level, and the engine is idling.

 

[yieldchase]

When measure the ATF level, the ATF temp is at 50°C / 122°F when the car is level, and the engine is idling.

Yeap, warm, level, and idling.

 

[murky]

I believe your Mazda dealer topped off the engine oil during new car inspection as that’s very easy to do. The same on engine coolant. I picked up my 2016 CX-5 right after it was unloaded from truck and I watched the tech doing the new car inspection tearing those protection films off as I special ordered my car. He wanted topping off the engine oil and coolant with some unknown oil and coolant (looks like tap water) sitting on his bench since both were low. I stopped him doing that and said I’ll top off these 2 fluids by myself, got Mazda moly oil and FL-22 coolant right from parts department and did it at home.

I actually checked the oil level on a couple of brand new CX-5’s at the time and they all at the same level like mine, a bit over a half between ADD and FULL marks on the dipstick. That made me feel batter that the low oil level on my brand new CX-5 isn’t unique.

We all know oil change overfill is almost a norm by the car dealers for some reason. And I believe your engine oil and many others were also overfilled during the new car inspection.

Halfway between Min and Max is the correct level. More than max is overfull. Less than min is underfilled. Anywhere in between is acceptable operating range.

If you expect to consume oil, it makes sense to put it above the mid mark, but Max is the limit, not the target.

 

[yrwei52]

Halfway between Min and Max is the correct level. More than max is overfull. Less than min is underfilled. Anywhere in between is acceptable operating range.

If you expect to consume oil, it makes sense to put it above the mid mark, but Max is the limit, not the target.

View attachment 328978

 

[N7turbo]

Gotta love contradictory statements.

"The level is normal if it is between the MIN and MAX marks."

"If it is near or below MIN, add enough oil to bring the level to MAX."

 

[yrwei52]

Gotta love contradictory statements.

"The level is normal if it is between the MIN and MAX marks."

"If it is near or below MIN, add enough oil to bring the level to MAX.

Yes, there’re more from Mazda such as these from Mazda Workshop Manual:

This’s fine with 0.48 quart of gear oil to fill the front transfer case to the brim of the fill hole.

But for rear differential, you do need about 0.75 quart of gear oil to fill to the brim of the fill hole, not stated 0.48 quart!

For those who have been doing gear oil changes for a long time, he/she should know filling the gear oil to the brim of the fill hole is a common practice for manual transmission and rear differential.

The same on engine oil. Every vehicle when it specifies oil capacity, it always means to the Full mark of the dipstick. But Mazda’s 4.8 quarts on 2.5L NA、and 5.1 quarts on 2.5T, can only reach a half way in between Full and Add marks of the dipstick. Unconventional ⋯

 

[murky]

Gotta love contradictory statements.

"The level is normal if it is between the MIN and MAX marks."

"If it is near or below MIN, add enough oil to bring the level to MAX."

Those are not necessarily contradictory.

If you fill it to max and it gradually is consumed, and you top it off when it gets near min, its condition most of the time will be between the Min and the Max and its average level will be near that midpoint.

If it were filled to the midpoint, and worked its way down near the min, it is losing or consuming oil. It makes sense to buy some buffer by filling as much as is safe.

If it isn't using or losing oil, there is little benefit to having more than the midpoint.

Overfull can be harmful. Anywhere in that range is fine and surely there is some margin on both ends for instantaneous condition.

 

[N7turbo]

Those are not necessarily contradictory.

I think they are. Take the logic of both statements into account. By telling the customer to fill to the MAX, they are saying "the level is not normal" if it is below MAX. Which contradicts the previous statement which says "normal" = "between the MIN and MAX marks".

 

[yrwei52]

Those are not necessarily contradictory.

If you fill it to max and it gradually is consumed, and you top it off when it gets near min, its condition most of the time will be between the Min and the Max and its average level will be near that midpoint.

If it were filled to the midpoint, and worked its way down near the min, it is losing or consuming oil. It makes sense to buy some buffer by filling as much as is safe.

If it isn't using or losing oil, there is little benefit to having more than the midpoint.

Overfull can be harmful. Anywhere in that range is fine and surely there is some margin on both ends for instantaneous condition.

The manual says "If it is near or below MIN, add enough oil to bring the level to MAX.", but it also says "The level is normal if it is between the MIN and MAX marks.“ So when oil level dropped near the MIN, it’s still within the NORMAL range, why would you want to add oil? And add enough oil to the MAX, not to any level in between?

It’s all about better safety margin. Keep the oil level at the MAX level protects the engine better when any accident of oil leak happens. I myself had an incident that the free Toyota new car maintenance oil change done on my 2018 Toyota Yaris iA and overfilled at least 0.5 quart as usual. I then drove 400 miles from San Jose to LA, only found the oil level didn’t register any on the dipstick the next morning. Turned out the Toyota tech “damaged” the drain plug gasket during the oil change and the oil was leaking out. If the tech didn’t overfill the oil with much bigger safety margin, my Yaris could have a damaged engine and got stranded somewhere on the I-5.

 

[sm1ke]

Engine oil level preferences should not be discussed in an ATF drain fill thread. There are other threads dedicated to engine oil level discussion, take the discussion there instead. Continued off-topic posts may lead to a "thread cleaning".

Back on topic please.

 

[murky]

Back on topic. With the transmission being a closed system, Mazda probably puts in the minimum amount they know is sufficient, and they probably do it very precisely and repeatably.

This is hypothetical, and I pretend no special insight into automatic transmissions or Mazda's in particular, but Imagine the safe operating amount is 80-100 units of ATF. They may say in the owners manual or indicator to fill to 90 because they are allowing margin for error.

At the factory they may choose to put in exactly 82 units with a process tolerance of plus or minus less than one unit. Then inspect or audit that and ensure that their process remains statistically in control.

The system may perform just as well, or even better, with 82 as it would with 90. But they can't trust customers to put exactly 82 when 79 might lead to premature failure.

 

[ruthrj]

Back on topic. With the transmission being a closed system, Mazda probably puts in the minimum amount they know is sufficient, and they probably do it very precisely and repeatably.

This is hypothetical, and I pretend no special insight into automatic transmissions or Mazda's in particular, but Imagine the safe operating amount is 80-100 units of ATF. They may say in the owners manual or indicator to fill to 90 because they are allowing margin for error.

At the factory they may choose to put in exactly 82 units with a process tolerance of plus or minus less than one unit. Then inspect or audit that and ensure that their process remains statistically in control.

The system may perform just as well, or even better, with 82 as it would with 90. But they can't trust customers to put exactly 82 when 79 might lead to premature failure.

Thats what I would do as the manufacturer. Fill a consistently repeatable minimum amount to ensure function. Why fill more at the factory then what is needed? .25 quarts x 100000 vehicles a year: 25000 quarts of transmission fluid saved per year. 100000 vehicles that meet spec without wasting resources ; )

 

[N7turbo]

Why fill more at the factory then what is needed?

Then ask the factory why they overfill the engine oil. Makes no sense.