My car suddenly started making this noise the other day. It starts around 35-40mph and gets louder until about 50-55 where it tapers off. I can sometimes feel it through the floor during louder moments too. Does anyone have any idea what it might be, or should I have the car looked at?

UPDATE:

Ok I think I found what caused the noise. A misplaced jack point badly caved in part of the floor directly underneath the front seat rear mounts. I'm pretty sure this is the cause since the noise started up the same day. I pulled out the seat, the carpet, and spent about 2 hours hammering the floor flat again, but it didn't change the noise at all. Based on where the floor was bent in, I'm guessing the noise is being caused by the driveshaft carrier bearings or where it connects with the tcase. Pic of the damage is attached. I also changed the drivetrain fluids but it didn't help either.

 

Did you get any aftermarket parts installed recently? Or done anything to the car recently?

 

Last thing I had done was a suspension shop fixed a lose bolt in one of the sway bar mounts. The day before, I rotated the tires. This issue started up about a day or 2 after both these things were done. Could it be caused by the front right tire having more tread on it than the front left, even though the front diff on my car is open?

 

I was hoping you would have said you just installed a FP turbo. They make that siren whining sound. When's the last time you changed drivetrain fluids?

 

Last time I changed drivetrain fluids was about 35-40k miles ago. I did all of them at once. Should I change them again? It's been so long, I don't even remember what fluids to use. I know I still have more of that diaqueen LSD gear oil though, since I got the big jug.

 

Drivetrain fluids should be changed every 15k miles and changed sooner if the car is ragged on a lot

 

Could be the wheel bearing. Mine sounded just like that and turns out both front wheels were shot. Parts were $130 each.

 

Thanks guys! I'm going to change the driveline fluids and if that doesn't help I'm going to look into changing out the wheel bearings. It seems to be coming from the front left so hopefully that will do it.

 

To check if it's the wheel bearings. Jack the car up and spin the wheel. If you hear the bearings in it like metal on metal that means all the lubricant is gone and you would need a new wheel bearing(hub assembly)

 

So, I just took it to the suspension shop today. They think it's the tire. That could make sense, since I did just rotate the tires a few days before it started. The tires on the front left and right are different tires, and the one on the right side is brand new while the one on the left is a year old, could that cause any problems beyond the noise? I thought I'd be okay because the front diff is open.

 

Ok I think I found what caused the noise. A misplaced jack point badly caved in part of the floor directly underneath the front seat rear mounts. I'm pretty sure this is the cause since the noise started up the same day. I pulled out the seat, the carpet, and spent about 2 hours hammering the floor flat again, but it didn't change the noise at all. Based on where the floor was bent in, I'm guessing the noise is being caused by the driveshaft carrier bearings or where it connects with the tcase. Pic of the damage is attached. I also changed the drivetrain fluids but it didn't help either.