What can cause a loud humming buzzing noise under front end that starts upon ignition and noise increases upon acceleration and only sounds quieter when coasting.The car has had this noise over a year now with no serious problems except that annoying loud noise. can it be transmission related. is it the differential and drivetrain?

SOURCE: 2006 Volvo S60 AWD rear humming noise

Wheel bearing is the most likely cause. Prob a 1.5-2 hour labor rate job in the shop.

SOURCE: why is my car buzzing or humming after i turn the ignition off?

If it's buzzing when the car is moving. it could be the wheel bearing making the buzzing sound. it needs to be replaced. you can probably hear it as being inside the hood.

SOURCE: my car is buzzing or humming after i turn the car off

Do you have headlight wipers? If so, wiggle the wiper arm and see if the buzzing stops.

SOURCE: 2005 XC90 T6 AWD making a whirling noise upon acceleration

Add me to the list. Just got back from a Volvo dealership in Chicago and was told the 'winding' noise we're experiencing during deceleration in our 2004 XC90 is due to a failing transmission,so i would suspect the same accelerating. hope all works out for you

SOURCE: After locking my car I could hear a buzzing sound

Sorry I dont have a solution just wanted my car is the exact same but is a merc, so hope someone out there can help us.