ATF fluild level

[ddagsyn]

hi
I was fixing to do a ATF drain and refill on my 2000 V6 camry and checked the ATF dipstick with the engine cold to record the level on the dipstick. I was surprised to see the level was at the hot level of the dipstick.
I quickly brought out my manual and couldn't believe that there was no mention on checking levels on the ATF dipstick.
The last person to touch the ATF was the dealership and that was about 20K miles ago.

Thanks

[DFBonnett]

The engine should be running, warm, but not blazing hot, and in park. How is the level then?

[ddagsyn]

After reading your post. I went outside to the garage and started the car.
I waited for about 10 min and checked the level. The level was between the cold notches. I then drove the car for about 10 miles on the freeway and checked it again and it read between the hot notches.

Puzzles me is that after the car sits overnight shouldn't the AFT dipstick read between the cold notches instead of hot notches. It was parked in a closed garage overnight with the temperatures in the mid 30 F overnight.

Thanks

[uibalnme]

^ it's basic physics. Any material will expand as its temperature increases. Overnight the ATF drains off of the transmission internals and down into the trans pan, increasing the level on the dipstick to the hot marks. When you start the car in the morning, a pump moves the ATF up into the transmission to lubricate the internals, and this drops the fluid level to the cold marks. Then as the ATF, and trans internals heat up, they expand a bit, and this moves the fluid level back up to the hot marks.

[JohnGD]

Absolutely. That's why on these transmissions the fluid level is checked at operating temperature, on level ground, after shifting through all gears. This allows valve body circuits to be filled. The cold level is only for quick reference (and this too with the engine running, so the ATF will get soaked up by the fluid circuits. However, this isn't the case with the engine off as Uibalnme mentioned, that's why the level is much higher when off).

It helps to do a few checks to get an idea of where the ATF level is on average. And then if you do your own drain, you can quickly measure what you drained out and put approx. that amount back in.

Newer transmissions will need to be checked in a specific temperature range, using a check plug kinda like in a manual transmission.

Originally Posted by uibalnme

^ it's basic physics. Any material will expand as its temperature increases. Overnight the ATF drains off of the transmission internals and down into the trans pan, increasing the level on the dipstick to the hot marks. When you start the car in the morning, a pump moves the ATF up into the transmission to lubricate the internals, and this drops the fluid level to the cold marks. Then as the ATF, and trans internals heat up, they expand a bit, and this moves the fluid level back up to the hot marks.