Rear end making noise

[AE86Batgirl]

So I just put 4.7 gears in my corolla and after I was done I can hear this humming sound from the back I have no interior so I know I will hear the gears but when I get to 40 MPH the humming sound is really loud I drove it around my neighbor hood and I hit 60 and it's just loud humming I even took it up high RPM in first and second nothing broke or anything just really loud humming is that normal???

[aukword1]

i dont know about your gearing but with the stock T-50 tranny you hear a loud humming when you are in fifth gear...

[asnfro]

Sounds like the backlash or pinion preload might be off. The a professional install the gears?

[gotzoom?]

Humming is usually bearings. If you have a panhard bar and/or 4-links with spherical bearings, they will transmit the sound into the cockpit more than if you have bushings too.

[AE86Batgirl]

It might be the pinion preload thanks guys I'm look into that today.

[Duy-]

accel / decel / neutral
does it make the same consistent through all these stages or only under certain conditions

[AE86Batgirl]

Only when I'm over 40

[Duy-]

okay after 40 mph, will it make the noise consistently or only under deceleration / acceleration

[gotzoom?]

If the sound stays the same whether coasting, accelerating or in between, it's bearings. If it's only under acceleration or coasting, it's gears.