How to Check Automatic Transmission Fluid. The trans needs to be at operating temperature, on level ground and running for most cars and trucks. Chrysler vehicles need to have the parking brake set and transmission in neutral. Honda car need to be at operating temp, engine off. Please check you owners manual to be accurate before proceeding. Come by and let us check it for you.  8204 Appalachian Hwy, Mineral Bluff,Ga. 30559. 706-900-9696