Roaring noise in front of 2003 olds alero gets louder as I accelerate, sounds like manual transmission needing to be shifted to next gear(this isn't a manual transmission

Harmonic balancer.

check wheel bearing...transmission output shaft bearing. noise is louder because when bearing slow down, they get louder from worn down ball bearing inside the cage, space is developing between the ball bearing..caused by lack of lubricate, or just worn out bearings

most likely if its a hum it could be tires , if its a roar it could be the drive train

support the vehicle on jack stands , start the engine , put in drive and let it idle, if noise is gone ...its the tires if not check the drive train ...start with fluid levels

If there's a loud roaring noise all the time, then your muffler probably has a hole in it, time to get a new full or partial exhaust pipe.

If the noise goes when it changes gear, then you've probably got a gear box or thrust bearing problem.

ask a local mechanic to have a look and a test drive as no technician on any site can give you an answer only a guess and that is the wheel bearings

This is your radiator fan... it willl pull air through when it is needed to keep your engine and coolant cool... if your engine needs to cool quickly it will blow harder making the "roaring" sound louder

If your noise is a low pitch rumble that gets louder the faster you go, it likely is a wheel bearing that is the cause. Another sign that the noise is from a wheel bearing is if the noise tends to get louder when steering one direction at a steady speed, and quieter when steering the other direction. A transmission noise does not change with the steering.

sounds like you wheel bearings need to be greased up. Good ideal to have full grease job anyways. U-joints, tie rods, and bearing especially

either repair or replace the transmission...sounds like the sensor went out

jack up front of car get hold of tyre an see if u get any play if u do u may get away with nipping them up a bit