checking the automatic transmission fluid (ATF)

there is only one important thing you need to know or remember:

**** always check the ATF WHILE THE ENGINE IS RUNNING 

it does not matter if you are doing the "cold engine check" or "hot engine check", the engine should be idling. your reading will be short 1 quart (.94 liter) if the engine is not idling. meaning it could say you have enough ATF fluid even if it is low or lacking 1 quart. it usually has about 7-8 quarts fluid so 1 quart could be significant.

the instructions in my 2007 mazda 5 manual is very confusing. here is what it says:

it says "When the engine has not been running ..." which made me think the engine should not be running when you check it. what it actually means is "when the engine is cold". you still have to go through the same process as the "hot engine check", which is:

another important warning is that each model and year has a specific fluid and your transmission will be ruined if you don't use the right fluid. the mechanic can easily make a mistake of putting the wrong fluid even if the mechanic religiously reads the owner's manual. example in my 2007 mazda 5 manual it says to use "ATF M-V". the dip stick also shows it:

the mechanic will wrongly interpret it as "Multi-Vehicle", especially the stores carry a lot of atf's labeled "multi-vehicle". but when i googled "ATF M-V", it showed amazon was selling a mazda specific atf "type M5". i called the mazda dealer to verify and they told me the atf for my 2007 mazda 5 should be type M5.  so V stands for roman numeral 5, not letter V. when i told the mechanic at autozone that V is roman numeral 5, he gave me "mercon V" atf. i googled it and turns out it's also different. so i just went to the nearest mazda dealership to buy the type M5 because none of the auto parts stores have it.

to make sure you have the right kind of transmission fluid and the the right amount, better to do it yourself. but you can't just dispose the ATF fluid in the usual oil collection centers. you need to bring it to your city's hazardous waste disposal center which usually is only open once a week for half a day (in the morning). google "hazardous waste disposal" for you city.


(for more of my knowledge bombs, click the "ian's knowledge bombs" banner at the top of this article and choose any article in the table of contents that piques your interest)