Problems with humming sound

Humming could be just about anything. Here are a few questions that may narrow it some. Does it make the sound with just the engine running, in park? Does anything you do make the sound louder or change in pitch, like speeding up, braking, turning? Does a change in road surface make a difference like blacktop, concrete, dirt? If you steer left and right while it is making the noise does it change? If you drive next to a wall or building can you hear the noise with the window down? Can you feel any vibration in the seat or steering wheel?

https://www.2carpros.com/articles/car-howling-noise

This is some info and noise for a bad wheel hub bearing:

https://www.youtube.com/watch?v=YvKWGjmPKoc

Is it a tire or bearing issue? Quick tire wear check.

https://www.youtube.com/watch?v=QWP6CSVw_V4

It gets louder when she drives. no noise while idling. I thinks it’s wheel bearing but the mission place said it could be the tire.

Both can create the same sound which makes it harder to narrow down. They can also make a lot of noise but when checked have no play. Couple ways to tell, drive it and while it makes the sound gently swerve back and forth. The idea there is the weight shifting will make a bad tire or bearing change in sound as the weight shifts. So say the noise gets louder when you swerve left. That usually means the opposite side is the bad one, so loud left means bad on the right, and louder right means bad on the left. Then put a jack under that side and check the tire for uneven wear what you want is nice even wear side to side and all around the tire. If you see tread worn in scalloped patches the noise could be the tire. Then check the bearing for play both in vertical and horizontal directions as the video shows. Another trick is to reach behind the tire and place a bare hand on the spring and then rotate the tire with your other hand. A bad bearing will usually show itself with the spring vibrating lightly in your hand. A tire won't show up that way.

Oh okay, thanks. but just a little low tire pressure wouldn’t cause a bad loud sound would it?

On a good tire it shouldn't although it isn't helping the tire. Now if the tire was at 10 psi when it should be 34 or so you may want to check it close for damage, but if it was say 28-30 with a required pressure of 34-36 then it shouldn't be an issue.

That is what I thought. do you have the procedure for hub and bearing in the manual?

You may want to check with Nissan first. That should be covered under the power-train warranty for 5 years 60,000 miles. No sense doing it yourself if they will do it free.

True, thank you.

They looked and said it was wheel bearing and they said axle had to be replaced in back, but it doesn’t make sense.

If they are doing it under warranty I would let them. Sounds can be misleading as to location because it can travel through the body of the vehicle. I've heard bad bearings that I would swear were in the front right, but when I put the chassis ear on them it turned out to be a rear bearing that was actually bad.

They ripped her off they charged her for rotating the tires just to find that the wheel bearing is bad, but they also said the axle is bad in the back but it’s not covered.

Did they say what was bad about the axle? There are multiple things that are possible but on an 18 I would be suspicious that it needs replacement unless it was bent or cracked. Oh if you wanted to look for the new part it is part number 55501-9VB1B looks like it has already been updated a few times, so it might not be a bad idea to contact Nissan corporate and talk to them if the local dealer insists it be replaced but doesn't give you a good reason. From the looks there are only the two bushings in it to go bad.

They just said the whole thing needed replacing it was doing something but didn’t say.

Is there any instructions on replacing the whole thing? it looks a lot different then other style axles.

I would find out what they claim the problem is. The only part that isn't easily replaced is the axle beam itself. Everything else is a bolt on part like the hubs, brakes and suspension. If the issue is something like a bad strut or bad springs then they are replaceable as individual parts. The beam itself is replaceable but unless it's damaged in some way I cannot think of a reason to replace it so I would try to find out what is actually wrong. For instance say they want to replace it because it is bent on one end or in the middle. Do you have any strange tire wear on the tires from that end? That might give a clue to a problem.
I just am not a fan of replacing expensive parts without knowing why.

I will find out more next Saturday they're going to look at it again when they put the wheel bearing in. so it’s a differential style axle so how's the beam accommodate that?

As far as replacing it, the manual parts are not really hard but the factory data assumes you are replacing the entire rear axle as an assembly with new hubs, brakes and all of that attached. In your case I would try to reuse all of that if possible which is why you need to know what is wrong. Wouldn't help you to replace the axle beam if the problem is really something else.

1. Remove the reservoir cap from the reservoir tank.
2. Remove the rear wheels and tires.
3. Loosen the flare nuts on the brake lines,
4. Remove the rear drum brake assembly.
5. Separate the parking brake cable (RH/LH) from the rear suspension beam and position the rear drum brake back plate (RH/LH) aside with wire. Refer to Exploded View.
6. Separate the brake hose (RH/LH) and the brake tube (RH/LH) from the rear suspension beam. Refer to .Exploded View.
7. Disconnect the harness connector from the wheel sensor (RH/LH). Refer to Exploded View.
8. Position a suitable jack under rear suspension beam.
Place the jack in the center of the suspension beam.
Do not damage the suspension beam with jack.
9. Separate the shock absorber (RH/LH) from the rear suspension beam and remove the coil spring (RH/LH).
Make sure the rear suspension beam is stable when using the jack.
10. Remove the rear suspension beam bolts.
11. Slowly lower jack, remove rear suspension beam from vehicle.

How do you mean different axle? You said the back axle, that is the rear beam suspension for a two wheel drive Kicks which was the only one sold in the US. I don't see any of the Kicks sold elsewhere which have a rear differential either.

I’ve never seen one like that I’ve always seen differentials but she hit a lot of potholes. I’m thinking for that to be bad it has to be bent most likely.

That could be the issue, which replacing the beam would correct for a while. It might be possible to bend it back as well, you might want to have it checked for 4 wheel alignment before replacing it though. That would show if it's bent and how much.

They did a alignment and Rotation so I’m guessing it probably is bent. they want cover it so is there anyway I can check the wheel alignment?

They should have a print out on the alignment. But unless it is eating tires I'm not sure I would replace it. What did they quote to replace it? A new beam is about $600.00 for the bare beam.

I don't think she will replace it until it starts causing problems.

I wouldn't, If you get a chance take a close picture of the tires that were on the rear and post them. If there is weird tire wear it may show up, but unless it's way out replacing a set of tires every 20-30 thousand might be cheaper. You could also take it to one of the chain stores that does alignments and rotations cheap and get a printout on it's current condition. Here there are places that do them for about $50.00 and that would give you a better idea of the problem, unless they give you a print out, if they do post it and we can look at what it might do if it's bad.

I will do that then I'll take pictures of everything and send it when I get a chance. will this question be still up if I send them?

Yep, just log in and it will still be here, forever, or at least until the internet finally crashes.