Guide ATF Drain/Fill

You have a 2018 CX-5 and you've already changed the gear lub from your front transfer case? This's the first time people here are reporting the gear oil in front transfer case is low!

Everyone who checked his/her rear differential gear oil from factory and all says it way low from the fill-hole! It requires ~0.75 quarts to fill up during the change but the manual says 0.48 quarts! This's for gen-1 CX-5 AWD, the manual says the capacity on rear differential oil for gen-2 CX-5 AWD is 0.37 quarts! It'd be interesting how much it really need. Please report back your findings.

For engine oil change, if you drain the oil long enough without using Fumoto valve, it would need 5.3 quarts of fresh oil to make the oil level at "Full" mark of the dipstick.
Maybe they're making an allowance for thermal expansion...(naughty)
 
You have a 2018 CX-5 and you've already changed the gear lub from your front transfer case? This's the first time people here are reporting the gear oil in front transfer case is low!

Everyone who checked his/her rear differential gear oil from factory and all says it way low from the fill-hole! It requires ~0.75 quarts to fill up during the change but the manual says 0.48 quarts! This's for gen-1 CX-5 AWD, the manual says the capacity on rear differential oil for gen-2 CX-5 AWD is 0.37 quarts! It'd be interesting how much it really need. Please report back your findings.

For engine oil change, if you drain the oil long enough without using Fumoto valve, it would need 5.3 quarts of fresh oil to make the oil level at "Full" mark of the dipstick.

I finally got around to the rear differential. So I did't measure what came out of the front. But it was for sure low form the factory, the fill plug was bone dry so I don't think fluid ever touched it. After filling the front the rear took almost every last bit that was left in the bottle. So for a 2018 one quart of diff fluid for both is perfect!

I'm glad I did it too, the fluid was nice and clean looking with the exception of a lot of shinny metal dust/flakes, so it was good to get that out of there at around 4k miles. The plug magnets for front and rear were also really dark full of metal dust before I wiped them clean with a rag.
 
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I finally got around to the rear differential. So I did't measure what came out of the front. But it was for sure low form the factory, the fill plus was bone dry so I don't think fluid ever touched it. After filling the front the rear took almost every last bit that was left in the bottle. So for a 2018 one quart of diff fluid for both is perfect!

I'm glad I did it too, the fluid was nice and clean looking with the exception of a lot of shinny metal dust/flakes, so it was good to get that out of there at around 4k miles. The plug magnets for front and rear were also really dark full of metal dust before I wiped them clean with a rag.
So is the factory rear differential gear oil low from filler hole like the front transfer case? It seems the capacity of rear differential gear oil is more than specified 0.37 quarts.
 
So is the factory rear differential gear oil low from filler hole like the front transfer case? It seems the capacity of rear differential gear oil is more than specified 0.37 quarts.

The capacity for the front in the manual is .48 qts and rear is .37 just like you mentioned. But neither looked like they were up to the fill hole from the start. So there is about .15 qts that are low between the two diffs which is close to 5 fluid oz. for both on the 2018 model that's about 2 1/2 oz each, so I guess that's not awful. But it could be if one is really low, and the other is on spec.

Definitely a good idea for new owners not to trust the fluid levels of a new car and run them for 75,000 or more miles before checking and/or replacing fluids.
 
I just finished a drain/fill on my ATF this afternoon with 49k on the clock. I removed the entire underbelly pan and the access hole next to the radiator drain. It made it super easy to access the ATF dipstick and drain the old ATF. I chose not to remove the air filter housing and snorkle. Using a long thin funnel with some additional hose (Advance Auto had both) made refilling the ATF less of a hassle. I checked the fill (after a brief ride to warm it up past the coolant light going out) was at the second "2" on the 122 marker. Almost exactly 3.5 qts came out and I put the same volume back into the transmission fill hole.

After the refill and a brief drive to move the gears and get it back up to operating temperature showed the level at the second "2" again.
 
ATF trans pan gasket available . What do folks think ?

https://www.amazon.com/dp/ (commissions earned)

At that price, the gasket is literally free.

edit: mixed reviews on gasket. some report splitting.

I just finished a drain/fill on my ATF this afternoon with 49k on the clock. I removed the entire underbelly pan and the access hole next to the radiator drain. It made it super easy to access the ATF dipstick and drain the old ATF. I chose not to remove the air filter housing and snorkle. Using a long thin funnel with some additional hose (Advance Auto had both) made refilling the ATF less of a hassle. I checked the fill (after a brief ride to warm it up past the coolant light going out) was at the second "2" on the 122 marker. Almost exactly 3.5 qts came out and I put the same volume back into the transmission fill hole.

After the refill and a brief drive to move the gears and get it back up to operating temperature showed the level at the second "2" again.

Good job. My have to try this route next time...but with eye protection.
 
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After the refill and a brief drive to move the gears and get it back up to operating temperature showed the level at the second "2" again.

Might want to doublecheck. At 122 degrees level should be in the box between the 2 lines on the dipstick.
 
⋯ I checked the fill (after a brief ride to warm it up past the coolant light going out) was at the second "2" on the 122 marker. Almost exactly 3.5 qts came out and I put the same volume back into the transmission fill hole.

After the refill and a brief drive to move the gears and get it back up to operating temperature showed the level at the second "2" again.
Did you have a chance to measure factory ATF level before you started doing anything? I now become to believe this's an important step for DIYers as the factory ATF level can be low according to many DIYers reported. In your case the ATF level seems to be too high from factory for some reason.

I agree with ColoradoDriver that you may have to re-measure ATF level with an OBDII reader for more accurate coolant temperature reading. The ATF level should be at the center mark area of the dipstick. And did you measure the ATF level with engine idling and dipstick fully seated?

So...doing my second drain and fill as I type this (waiting for fluid to finish draining).

This time I think I measured correctly. I moved the airbox out of the way, but left it attached. Started the car and waited for the cold temp blue light to turn off. Then with the car still idling, checked dipstick. Assuming that's what I am supposed to do, I think I am still low as it should be closer to the middle eh? Or the other line perhaps?

Edit: Car was still level, not on ramps yet.

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Did you have a chance to measure factory ATF level before you started doing anything? I now become to believe this's an important step for DIYers as the factory ATF level can be low according to many DIYers reported. In your case the ATF level seems to be too high from factory for some reason.

I agree with ColoradoDriver that you may have to re-measure ATF level with an OBDII reader for more accurate coolant temperature reading. The ATF level should be at the center mark area of the dipstick. And did you measure the ATF level with engine idling and dipstick fully seated?

Good points. My initial reading from the ATF dipstick was at the second "2" on the 122 with the car warmed up and the engine off. It would be interesting to hear, on a properly measured fill, what the reading from the ATF dipstick was with engine running and not running. I did not see any frothing or bubbles on the dipstick which is usually an indication of an overfill.
 
Good points. My initial reading from the ATF dipstick was at the second "2" on the 122 with the car warmed up and the engine off. It would be interesting to hear, on a properly measured fill, what the reading from the ATF dipstick was with engine running and not running. I did not see any frothing or bubbles on the dipstick which is usually an indication of an overfill.

To get the proper reading you have to measure with engine idling. Easy said than done, I know.
 
To get the proper reading you have to measure with engine idling. Easy said than done, I know.

Ahhh I remember now. That's why I did the measurements from above and while moving the intake system aside....its tricky though but it can be done. That oil was super slick too.
 
IIRC more fluid will be resting in the pan while engine is off than on. I suppose this is why you have to always check level with engine running . That is what I have seen on my GX anyways.
 
Good points. My initial reading from the ATF dipstick was at the second "2" on the 122 with the car warmed up and the engine off. It would be interesting to hear, on a properly measured fill, what the reading from the ATF dipstick was with engine running and not running. I did not see any frothing or bubbles on the dipstick which is usually an indication of an overfill.
Like ColoradoDriver said, you have to keep the engine idling while taking the read on ATF level. Your read was high is because your engine is not idling. The main concern is under-fill not the over-fill, as many have found the factory ATF level is low. If you use the same volume of drained out ATF to refill, chances are you may under-fill the ATF as 3.5 quarts seem a bit low to refill. 3.7 ~ 3.8 quarts are more or less the right volume.
 
Here is ATF level measurement procedure from Mazda factory service manual:

Nice!

ATF level should be at the central marker area on the dipstick at 122F while the engine is running. Make sure to shift into all possible gears during the warm-up.

Judging by the color of your drained ATF, I may consider another drain-and-fill if I were you.

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Like ColoradoDriver said, you have to keep the engine idling while taking the read on ATF level. Your read was high is because your engine is not idling. The main concern is under-fill not the over-fill, as many have found the factory ATF level is low. If you use the same volume of drained out ATF to refill, chances are you may under-fill the ATF as 3.5 quarts seem a bit low to refill. 3.7 ~ 3.8 quarts are more or less the right volume.

I pulled the inspection plate/cap under the car when I got home today from work (10 mile drive) and removed the dipstick while the car was still running (and warmed up). It was right on the center block (middle) of the dipstick. After cleaning it off and reinserting, it showed again to be in the center.
 
I pulled the inspection plate/cap under the car when I got home today from work (10 mile drive) and removed the dipstick while the car was still running (and warmed up). It was right on the center block (middle) of the dipstick. After cleaning it off and reinserting, it showed again to be in the center.
From your description I do believe your ATF level is a bit low, like it was from factory.

Like Mazda's factory service manual and ATF dipstick say, you have to measure ATF level with its temperature at 122F. Apparently your ATF temperature could reach 192F when your engine was fully warmed up at the time you took the measurement. ATF expands a lot more than engine oil when their temperatures are getting warmer. That's why all car manufactures will specify ATF temperature when ATF level is measured. Your ATF level is right on the central maker area when ATF was hot, it'd be below that level when ATF is colder at 122F. You need a bit more ATF to bring up thd level at 122F.
 
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