Got a question for all the Toyota enthusiasts..... Rear axel is leaking gear oil and making a humming noise when on the accelerator.... Does anyone know what the humming noise could be ...driveshaft ... Bearings in axel?....not quite sure humming only happens when on the accelerator ... Thanks again guys for the time to read over the post ... Chow

 

Is it low on gear oil from leaking? Also, where is it leaking from? Can also check driveshaft u-joints

 

Check/change your diff oil first with heavy weight. You diff oil will be low, if not gone, if you have an axle seal leak Prolonged low oil could cause the gears to be worn, have way too much backlash and causing a whine noise. Mine are shot and they scream on the highway.

 

I would bet its excessive backlash. Mine hum like you describe. Also might check all the bolts around your differential. Mine was leaking and I couldnt figure where it was and then I discovered one of the nuts on the differential housing had come loose. Tightned it and it hasnt leaked a drop since.

 

On your way, you can check the wheel bearings. Just lift the wheels off the ground, and turn them with your hand. If you can feel anything at all, you need to replace the bearings.

But if you're leaking anywhere in the rear end, the whine is probably the differential, low on oil.