Off, but the engine should be warm. (wrong) Read below:
It all depends on the make and model of your car. Some cars require you to check it with the engine running (could be in park or neutral). Some cars you check with the engine off but motor warm and on newer cars 2006-2012 a dealership has to check it.
Check the automatic transmission fluid
If your car running less then 10 minutes then it's considered a car with cold transmission fluid (fluid should be in the region of cold level marks, but not lower), if more then 10 minutes then it's hot (fluid should be in the region of hot level marks, but not higher). When you check transmission fluid level your car should be running.
you need to check your transmission fluid while your car or truck is running to get accurate results
It is advisable that you check with your local mechanic as to when you should get your transmission fluid changed in your car. Ideally, it should be changed every 3 years or so if the car is driven aggressively.
You can check the motor oil or the transmission fluid.
check the fluid with the car off
Maintaining transmission fluid in a car is important to keeping a car running smoothly. A person adds transmission fluid in the same tube of the dipstick, where they check the transmission fluid.
the car has to be warm running, in park, and level to check the transmission fluid
It is important to check and maintain fluid levels in a car. To check the transmission fluid, a person looks for the red cap under the hood, this is the transmission dipstick.
Transmission Fluid Level Check Volkswagen Beetle (1998-2010) Our research indicates that your vehicle does not have a transmission fluid dipstick. These types of transmissions are designed to be maintenance free. In order to check the transmission fluid, your vehicle likely has check valve on the bottom of the transmission on the bottom of your car. Your car must be level when the fluid is checked and we therefore recommend having a mechanic with a hydraulic lift or underground bay check your transmission fluid.
let the car warm up to normal running temp and check the fluid on the transmission dipstick. the dipstick should be torwards to back of the engine on the passenger side.
All fluids should be checked when you purchase fuel. All fluids except for the transmission fluid should be checked with the engine off and at operating temperature. The transmission fluid should be checked the engine running and the transmission in PARK if automatic or NEUTRAL if manual.