2010 Hyundai Sonata Owner's Manual - Page 230

6 DO-IT-YOURSELFMAINTENANCE 16 G110D03O-AAT Checking the automatic transaxle fluid level 2. After the transaxle is warmed up sufficiently (fluid temperature 70~80°C (158~176°F), for example by 10 minutes usual driving, move the shift lever through all positions then place the selector lever in "N (Neutral) or P (Park)" position. Fluid level should be within "HOT" range OHD076045N ONF078008 The automatic transaxle fluid level should be checked regularly. Keep the vehicle on the level ground with the parking brake applied and check the fluid level according to the following procedure. 1. Place the selector lever in N (Neutral) position and confirm the engine is running at normal idle speed. 3. Confirm that the fluid level is in "HOT" range on the level gauge. If the fluid level is lower, add the specified fluid from the fill hole. If the fluid level is higher, drain the fluid from the drain hole. 4. If the fluid level is checked in cold condition (fluid temperature 20~30°C (68~86°F) add the fluid to "COLD" line and then recheck the fluid level according to the above step 2.