Whats the best way to get a accurate reading on transmission fluid? I just cant seem to get a good reading and make sure i have a enough fluid.
This for a RL 2008. the reason I'm is that i seem to get a whining noise once the vehicle is warmed up, when its in gear. The noise goes away when its in park. I thought about replacing the fluid to see if that helps with nosie but wanted sure that i can get a good reading before i proceeded.

 

park the car at relative level parking then check the ATF when the car is cold for accurate reading.