High Pitch whine at 3000 RPM

[sbaxter]

It started before I replaced my transmission (twice), and is still there today, so it's not my transmission.

It's actually present at all times, but you can only hear in the back seat. When I hit 3000 rpm the whine kicks into high gear and permeates the entire car, but again louder in the backseat.

Does not occur when in Neutral, haven't tried to hit 3000 rpm in reverse....

[triz]

Check your idler or tensioner pulleys. OCV valve?

The fact the way it dissapears in neutral or reverse kind of boggles me though. I was thinking throwout bearing.

[sbaxter]

Pulley assembly looks fairly straighforward, looks like my project for next weekend.

[sideshowalan]

FWD or AWD?
If it's AWD you should check your rear transfer oil

[sbaxter]

FWD Base model.

[Chiadog]

Broken motor mount?

[circuitsmith]

If you rev in neutral does it whine?
Try (temporarily) taking off the serpentine belt.
It's safe to run the engine for 15 seconds or so without the belt.
If the noise goes away it's the idler pulley or a bearing on an accessory (alternator, p.s. pump, water pump or AC compressor).
Spin each one by hand and feel for smoothness.

[sbaxter]

It does not whine when in neutral.

[jolt]

When you said back seat of car is louder, I am thinking fuel pump in tank making noise but when not in gear - no noise. Is this coasting in neutral or stopped? It could be the belt, pulleys, alternator bearings, water pump bearings, etc. on the motor but that noise should come from the front. You need to provide more feed back and information, is the whine a steady pitch or does the pitch change as a): engine rpm changes, b): vehicle speed changes? Does the noise change if you are coasting or turning right or left?

It may be a shield on the exhaust or a loose shield under the car that is buzzing. A broken exhaust hanger that is letting the exhaust pipe hit a part of the under body.