Helicopter Sound from Transmission
 

Hey guys, I'm getting this knocking/helicopter sound from what I think is the transmission (I could be wrong dont quote me on that lol)

It happens when I'm rolling (in gear) but not pushing down the gas and it happens also when I roll to a stop light in neutral.

No sound when I'm accelerating and no sound at idle when at a stop.

I don't think its a plastic cover under the car flapping due to the wind because this happens at 10mph too, as well as when rolling backwards into a parking spot.

Any ideas on what this might be?

Last time I heard a "noise" coming from my car (turned out to be my fender liner hitting my tire) I tried taking it to toyota to get it checked out but due to my car being "Heavily modified" (coilovers and rims) they wanted to charge me $200 to inspect the car. So i wanna see if we can figure this out before I gotta take it to toyota.

MT?


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yes its a manual sorry bout that

Pretty sure it's normal. All of my friends get it including me

this isnt like a light tapping sound, this is helicopter landing on the roof of my car loud and even louder when i roll the windows down

Almost like a loud flywheel chatter makin it sound like a diesel truck? Or kind of S grind? It's been a while since I heard it. I jus coast in nuetral

Really loud chatter, idk if its the flywheel. Car still drives perfectly fine, just when I coast in neutral or coast in gear I hear it and the tempo of the rattle is even and speeds up and slows down with the car speed. The weird thing is when im driving facing forward it sounds like its coming from the bell housing area. but when i turn my hear to the rear of the car it sounds like the driveshaft/diff

No grinding gears, doesnt sound like anything is gringing, just... helicopters lmao thats the best way to describe the sound

Does it speed up and down with the wheel speed, with the driveshaft, or some other speed? To what can you match the period of the "wop wop wop?"

speeds up evenly with wheel speed, slows down when coming to a stop sign or light

any chance it might be a bad cv joint?

or a nail/screw in the tire...thats what it was for me.

It's possible it's a bad cv joint but I've never heard one that made noise while coasting. Doesn't mean it can't happen.

Whatever it is, it's back there. Get it up on jackstands, get underneath it and spin the wheels.

If it follows wheel speed it could be a bad cv joint/axle considering you are lowered which is what kills them, just because its not entirely broken doesn't mean it is, it could just be near its failing point or damaged slightly. I'd make a thorough inspection of the wheels and fenders to make sure nothing is stuck or a heavy plugged nail in a tire.

You also said that it doesn't do it when accelerating which would make me think it'd come from the front due to the car lifting up and the rear coming down but you say it comes from the center'ish area so that gets ruled out, if it gets louder when braking i'd check the front side first, lift your car and wiggle each tire side to side to also rule out wheel bearings, if theres and play in it that could be a cause.

ruled that out. way to loud and violent sounding to be a nail haha

yeah i was talking to stay crushing and he was saying axles/cv joint so im gunna hit up the facebook buy sell see if someone has an extra set of stock axles that i can throw in to see if that fixes it or not. if so ill invest in some brand new ones after those break

thanks for your help bro!