Whine/hum from rear diff after changing axle seal

So I changed out the passenger axle and the drained/replaced the rear differential fluid. When I put everything back together and started the engine with entire rear axle lifted, I heard a somewhat high-pitched whining/humming sound coming from the differential. The sound starts when the transmission is in Drive and gets louder as I accelerate. It does not make the sound in Reverse. It definitely did not make the sound before I removed/replaced the axle and changed the gear oil. Here is a video that records the sound:

https://www.youtube.com/watch?v=ma2vkAldqpU&feature=youtu.be

Any idea what this may be? Many thanks in advance.

You can hear the sound grow louder as I accelerate. And that it doesn't make the sound when I switch to Reverse.

this is a 2002 Tacoma TRD V6 auto

 

Once oil leaks out those seals the axle bearing is a good as trash. The oil washes out the grease in the bearing

 

Thanks, by axle bearing do you mean wheel bearing?

 

Make sure you have enough fluid with the wheels on the ground. Jack up one side so the tire is just off the ground and bring it up to speed and listen. Now drop that tire back on the ground and lift up the other tire and give it a spin. If you only hear the noise when a certain tire is off the ground, then that wheel bearing is bad. Try this first and see what you hear.

 

Thanks for the reply. I'm not sure what you mean by lifting up only one tire and bringing it up to speed. If one tire is touching the ground, won't it propel the truck forward when I put it in drive with the engine running?

 

As long as you don't engage the rear diff lock, if you have one, you will only spin one tire at a time. It would be like getting stuck in the mud or snow, you just have no traction in that one wheel so it spins. If you have 4x4, take it out of 4 wheel and run in 2x4. This way you only send power to the rear axle. If you are still not sure, let off the brake reeeeeal slowwwwly. Or look at youtube.
https://www.youtube.com/watch?v=cdRpnK5MGQ8
https://www.youtube.com/watch?v=_hId3Dx2H_4

 

wamego:
thanks for the explanation and videos. I did exactly as you said (with big stones in front of all non-elevated tires). The wheel that I did not change was completely quiet. The wheel that had the failed axle seal made an awful grinding sound when I accelerated. The video below captures this sound, much worse with acceleration. My question is whether this is indeed likely the wheel bearing or if it may be an issue with the differential. Thank you again for the great suggestion and help.
https://youtu.be/QM-eUvWgRAs

 

A bad wheel bearing could definitely cause your seal to fail, so that may have happened. The funny thing is that it could also be the other way around, but is usually the wheel bearing that fails first and causes the axle to not ride in the center of the tube which widens the seal and oil leaks past.

 

I would say that yes, that wheel bearing is bad. Like nzbrock says above, the axle is not centered now and pushed on the seal which caused the leak. Now you have a good place to start. Be careful taking out the new seal and then replace the bad bearing with a new one. Maybe just get a new seal again just to be safe.

 

Looks like you'll be taking it back apart. Here's some reading on the intricacies of the axle seals if you're interested:

https://www.tacomaworld.com/threads/new-axle-seals-leaking.459642/page-2

 

so i bought these parts:
- 90363-40068 Bearing
- 90313-54001 Axle Shaft Oil Seal
- 90520-36045 Bearing Snap Ring
- 42423-20010 Bearing Retainer
and took them and my axle to a machine shop, who charged $60 to install them. I also installed another axle seal (90310-50006). Here is the result (again with only one wheel raised):
https://youtu.be/GXse7DvUgjQ
to me, it sounds essentially the same as before I replaced the wheel bearing:
https://www.youtube.com/watch?v=QM-eUvWgRAs
I still hear that whine/grinding sound; I have no idea what that is.

I'm gonna assume the wheel bearing was never bad, but rather it was just the axle seal all along. anyone interpret this differently?

 

@Dirty Pool

 

did you mess with the brake adjustment?

 

not at all. but i did remove the e-brake lever to take the assembly to the machine shop. i didn't touch any of the brake shoe springs. are you thinking its the shoes that are rubbing?

 

I agree. It sounds the same to me too. I've never replaced an axle seal on a car, but I can't imagine the seals I've replaced on other equipment would cause that sound. I wish I could offer a suggestion or advice.

 

yes.

 

Is this noise audible in normal driving?
It almost sounds like the side/spider gears spinning way way faster than they do in normal driving due to one wheel not spinning.
While the side/spider gears are bevel type they are still essentially straight cut gears with the propensity to make noise. There could be a host of reasons why the noise is not "heard" on the other side.
OP, you have the e-locker. Go ahead and lock it and do the noise check with both wheels off the ground. This will eliminate any turning of the side/spider gears due to "differential" action. If all is quiet, go about your life. If the noise is still there then continue the quest.

 

OP maybe my ears are bad but all I hear is tire noise. How high off the ground are you and does noise change the higher you get it?

 

Crux: I'm about 2 inches off the ground in the last video, it was a little higher (maybe 3") in the first video. It doesn't seem to make a a difference if higher or lower. What do you mean by tire noise?