Whining noise with acceleration. I’m thinking maybe gearbox but I’m not sure.

[Acr314]

Bought a used fiesta st and I’m hearing a noise coming from the front end. It happens every time I’m on the gas pedal when cruising and also under any load. I usually start hearing it in second as in first it’s pretty slow. I hear it through the rest of the gears and gets louder with rpms. Any ideas? Is it worth fixing if it’s the gearbox or differential?

 

[Acr314]

I should also add it’s older as a 2007 and around 120k miles

 

[Clint Beastwood]

Bought a used fiesta st and I’m hearing a noise coming from the front end. It happens every time I’m on the gas pedal when cruising and also under any load. I usually start hearing it in second as in first it’s pretty slow. I hear it through the rest of the gears and gets louder with rpms. Any ideas? Is it worth fixing if it’s the gearbox or differential?

Might be hard to get much feedback on that gen of ST, here, it's overwhelmingly newer ST's/USDM - if you haven't already might want to go check out the less US focused forum(s) as well.

 

[Ecmdrw5]

So the pitch increases with road speed and not engine RPM? It's in the drive train somewhere. Double check that it has transmission fluid. It's possible it could be a wheel bearing but the pitch seems a little high for that. If it didn't indicate a problem I would say it sounds cool. Almost like you have straight cut gears. Good luck and welcome to the club.

 

[sean2e]

Bought a used fiesta st and I’m hearing a noise coming from the front end. It happens every time I’m on the gas pedal when cruising and also under any load. I usually start hearing it in second as in first it’s pretty slow. I hear it through the rest of the gears and gets louder with rpms. Any ideas? Is it worth fixing if it’s the gearbox or differential?

Find anything in the end? I also have one here in Australia with a similar noise issue.... Mine isn't as high pitched but starts about 1.5k RPM & its pitch increases from there under load.

 

[sonicmn]

Bought a used fiesta st and I’m hearing a noise coming from the front end. It happens every time I’m on the gas pedal when cruising and also under any load. I usually start hearing it in second as in first it’s pretty slow. I hear it through the rest of the gears and gets louder with rpms. Any ideas? Is it worth fixing if it’s the gearbox or differential?

It may be worth swapping tires if you have the ability. my Blizzak's were noisy and it sounded like gear whine, but in reality it realized in the spring that it went away immediately when I put my summer tires back on.

 

[TyphoonFiST]

Carrier bearing on the passenger side cv axle*

 

[Pablo Pistoffo]

Right after I installed my tune, I noticed a significant whine under heavy acceleration, but it was my spouse.

 

[LilPartyBox]

Flush the tranny fluid for a quality lubricant. And as @TyphoonFiST pointed out, carrier bearing on the axle's intermediate shaft. Rotating tires is a quick, but not always reliable, way to see if that's the cause