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- #41
Bad rear wheel bearing?
- Thread starter linuxgod
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I asked taco2cruiser whether my greasy rear ABS sensors were a bad sign and he said it happens sometimes on totally normal trucks. So I think the bad sensor actually going bad and throwing a code is a good sign, but the sensors themselves being wet isn’t.
I know we are driving different trucks, but in my case pulling the front driveshaft then driving with the center diff locked didn’t change the sound. With no torque/load on the front CVs in this circumstance if they were the source I’d expect to notice a change. But again this is my truck not yours. And I get that you are just going down the list.
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- #43
I'm not so sure. There wouldn't be a load on the CVs, but they are still spinning. The front gears are rotating too so long as the CVs are attached. I don't feel like the noise changes based on the load (heavy or light foot, CDL locked or unlocked, etc). But the speed and volume of the noise do vary depending on my speed, and I'll hear it even when in neutral or braking down to about ~15 mph.
Either way I'll be able to rule out diff-related noises in a few weeks since the re-gear should cover all of those bearings. The big question is how much "while I'm in there" other stuff do I want to do. The driver's CV seems like it's worth rebooting (and inspecting) since it was rebooted about 45k miles ago, it's a non-OEM boot, and I actually ran into issues right after the reboot where it was slinging grease out and I had to pull the CV clamps (which weren't tight enough) and put on some worm-drive clamps. So it's possible the CV is actually low on grease and wearing oddly, or something. (OTOH I'd expect a bad CV to click, and mine doesn't, so WTF do I know?) Also my wife, my kids, and Rick at ChiTown all agree with me that though it's not entirely directional the sound does seems to come from the front, even after the tire rotation.
The passenger's CV was also rebooted, but it had a tear in the outer boot and Toyota did a re-reboot of that one at around the 90k mark. So while that *could* be an issue, honestly I have more confidence that one was done correctly...
If the gears and CV reboot don't resolve it then I'm confident it's either a bad rear bearing or my tires are absurdly loud without showing any significantly odd wear patterns.
All that said my theories have been wrong enough times that who the heck knows
My gut is that a bad CV would reflect some change in load with a change in noise, and as you point out I'd expect some noise on turning. One caveat to the turning detail is steering angle greatly impacts outer cv joint angle, but doesn't change the inner very much. If it were an inner joint going bad, this specific troubleshooting tip might not apply.
Interesting.
I replaced the sensor and the new one was immediately coated too, and I was a proud code owner until the rear wheel bearings were done. The other side was 'clean'. I figured it must be the failed bearing. Didn't prevent me driving another 500 miles or so on it before I could get over the mountain to Nitro's shop.
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- #47
Thanks @bloc. That's very cool how quickly you can tell.
Is the noise you hear (without the chassis ears) while driving high pitched white noise like that or is it a lower pitched drone? (I tried to record mine but my phone mic doesn't seem to pick up the sound, which is weird since I feel like it's in the 80-120Hz range.
Does the pitch vary with speed or just the volume? IIRC you said before it was noticeable over a small range, but I'm wondering if the chassis ears picked it up across a much wider speed range or if it really only appears in that narrow speed band? I hear noise at low speed and it continues up through highway speeds. Pitch doesn't change much but the volume (intensity) does. Mine has been going on for a while though, slowly getting louder.
My mechanic used a stethoscope while it was on the lift and he said the bearings were quiet. I'll see if this persists once the re-gear is done in 2 weeks. If so I will buy or borrow a set of chassis ears to track this down. (Edit: I figure since I'll have to change out the rear fluid after 500 miles if it is a bad rear bearing it won't be any additional labor to wait and test it)
Is the noise you hear (without the chassis ears) while driving high pitched white noise like that or is it a lower pitched drone? (I tried to record mine but my phone mic doesn't seem to pick up the sound, which is weird since I feel like it's in the 80-120Hz range.
Does the pitch vary with speed or just the volume? IIRC you said before it was noticeable over a small range, but I'm wondering if the chassis ears picked it up across a much wider speed range or if it really only appears in that narrow speed band? I hear noise at low speed and it continues up through highway speeds. Pitch doesn't change much but the volume (intensity) does. Mine has been going on for a while though, slowly getting louder.
My mechanic used a stethoscope while it was on the lift and he said the bearings were quiet. I'll see if this persists once the re-gear is done in 2 weeks. If so I will buy or borrow a set of chassis ears to track this down. (Edit: I figure since I'll have to change out the rear fluid after 500 miles if it is a bad rear bearing it won't be any additional labor to wait and test it)
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Mine has a noticeable rumble/drone from 10mph up, a lot like mud tires, but between 74&79 or so it must hit a harmonic because it gets noticeably louder, to the point you can faintly feel it through the seat and floor like a driveline vibration. Above 79 it gets noticeably quieter but is still there. Then if going really fast like 95+ it picks up again.That is what had me so intently focused on the driveshafts for so long. Interestingly when I switched to p-metric road tires on 20s from an LX it got louder at all speeds and the 74-79 harmonic broadened to 74-84+. Maybe less sidewall meant less damping in the tire and more vibration was getting transmitted to the axle/suspension.
I’m betting you have a rear bearing going bad, and I think this tool is the way to narrow it down.
Edit: also, both rear bearings were silent through a stethoscope with the vehicle on jack stands and in Drive, but with no load on the wheels/tires.
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- Thread starter
- #49
ah ok aside from the extra volume above 70 that sounds a lot like what I have been experiencing. Dang it
Bah. I’ll start looking for a set of chassis ears
Bah. I’ll start looking for a set of chassis ears
- Thread starter
- #50
Ok I caved this morning and ordered a set off Amazon. They're ~$100, and should be here Friday. Not sure if I'll sell them when I'm done or eat the cost and leave them in my garage for some future issue.
@bloc, where did you end up clipping these? I assume in the rear I can just clip to one of the hub bolts, but in particular what did you do up front?
@bloc, where did you end up clipping these? I assume in the rear I can just clip to one of the hub bolts, but in particular what did you do up front?
I’ll take some pictures when I get home from the station. You’ll also need a bunch of zip ties.
Other side is a mirror image. In the rear I went along the LCA, jumped over to the inside of my sliders, then up to the front door. Front I zip tied it to the brake line, put it behind the splash shield, one zip tie along the frame, then around the body mount and to the slider.
The rear bearing carrier bolts seem like a natural spot but the clamps weren't big enough. Similar story for the front.. but the brake line bracket was securely bolted to the knuckle and I considered it good enough.
The rear bearing carrier bolts seem like a natural spot but the clamps weren't big enough. Similar story for the front.. but the brake line bracket was securely bolted to the knuckle and I considered it good enough.
You may have seen in my thread I got the axle out today. Key bit of info I missed when I pulled the abs sensors.. I didn’t dry them off. If I had I would have seen the one on the side of the bad bearing had some wear on it. This could be a very easy diagnostic, it’s a single 10mm nut and the sensor slides out. If you have the groove, that side is compromised.
- Thread starter
- #55
Yep I saw that, I've got a watch on your thread 
That's a good find. I may pull mine this weekend just to check when I set up the chassis ears. If it turns out mine has a similar wear pattern it would be a good inspection for others. Not sure if this will show up in every scenario but worth trying since it's pretty easy.
Not looking forward to this only because it's supposed to be single digits here this weekend; but since it's unlikely to warm up to tolerable temperatures until April I'm gonna fire up the space heater and just power through it
That's a good find. I may pull mine this weekend just to check when I set up the chassis ears. If it turns out mine has a similar wear pattern it would be a good inspection for others. Not sure if this will show up in every scenario but worth trying since it's pretty easy.
Not looking forward to this only because it's supposed to be single digits here this weekend; but since it's unlikely to warm up to tolerable temperatures until April I'm gonna fire up the space heater and just power through it
- Thread starter
- #56
As noted in @bloc's thread, my rear sensors looked fine - no grooves.
Did a run with chassis ears hooked up today. Two videos linked. First one is at 70mph where I cycle through all 6 mics, the second is at 20mph where I skip the diffs and only listen to the wheels. For those debugging with me, the order is
1. Left (driver's) Front
2. Front diff (skipped in the second, 20mph video)
3. Right (passenger's) Front
4. Right (passenger's) Rear
5. Rear Diff (skipped in the second, 20mph video)
6. Left (driver's) Rear
In the 70mph video #1 (LF) seems quieter than it is in person. Compare to #3 (RF) and there's a huge difference in volume.
In the 20mph video #1 definitely sounds "clicky" to me.
Did a run with chassis ears hooked up today. Two videos linked. First one is at 70mph where I cycle through all 6 mics, the second is at 20mph where I skip the diffs and only listen to the wheels. For those debugging with me, the order is
1. Left (driver's) Front
2. Front diff (skipped in the second, 20mph video)
3. Right (passenger's) Front
4. Right (passenger's) Rear
5. Rear Diff (skipped in the second, 20mph video)
6. Left (driver's) Rear
In the 70mph video #1 (LF) seems quieter than it is in person. Compare to #3 (RF) and there's a huge difference in volume.
In the 20mph video #1 definitely sounds "clicky" to me.
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- #58
The rears are similar levels of noise to each other. Not silent, but the LF is actually louder than both of them. The LF is similar volume level to the front and rear diffs, whereas the rear bearings are quieter (but still audible) and the FR is near silent. I'm thinking LF issue since the LF is much louder than the RF, but they're both clipped on at the same place on each wheel
I do hear the clicking in the LR you mentioned in the audio post. But to me the diffs are much louder than any of the wheels. Of the 2 methods of listening, I prefer the one without the diffs between the L and R hubs. The loud diffs distract from the ability to directly compare L and R. Because of the speed-related harmonics Bloc mentioned, you might want to try other speeds too.
These chassis ears are the coolest things. Never used one and it's interesting to hear what noises go on in the drivetrain.
@linuxgod, you said the noise is pretty prominent... can you tell which channel is making the noise with a sound signature that best matches what you hear at the drivers seat?
You might try to mic other parts of the drivetrain as well if you can't seem to nail down which wheel bearing. It could be the joints in the front or rear driveshafts, transfer case, etc.
@linuxgod, you said the noise is pretty prominent... can you tell which channel is making the noise with a sound signature that best matches what you hear at the drivers seat?
You might try to mic other parts of the drivetrain as well if you can't seem to nail down which wheel bearing. It could be the joints in the front or rear driveshafts, transfer case, etc.