Possible reasons for the automatic transmission humming when turned on:
*Low transmission fluid level: Check the fluid level and add it to the required level.
* Contaminated or poor fluid quality: Transmission fluid becomes contaminated and loses its properties over time. Replace fluid and filter.
* Worn or damaged gears or bearings: Due to normal wear and tear or extreme stress, gears or bearings can become worn or damaged. This may result in a buzzing noise when shifting gears.
* Incorrectly adjusted shift cable: Incorrectly adjusted shift cable may result in difficult shifting and a droning noise.
* Torque Converter Problems: The torque converter converts engine power into torque. If the torque converter is faulty, it may make a humming noise.
* Damage to sun or planetary gears: The sun and planetary gears are responsible for shifting gears. Damage to these gears can result in humming noise.
* Fluid pressure too high: If the transmission fluid pressure is too high, it may cause a humming noise.
* Clogged Transmission Cooler: A clogged transmission cooler can cause the fluid to overheat and cause a humming noise.
Steps to resolve the problem:
* Check the level and condition of the transmission fluid.
*Adjust the shift cable as necessary.
* Inspect the transmission for damage or malfunctions.
* Replace worn or damaged parts as needed.
* Clean or replace the transmission cooler.
Have your transmission diagnosed and repaired by a qualified mechanic to avoid further damage.