Normal manual transmission noise?

[Avery4]

Hello everyone, I just swapped a 5 speed transmission into my 05 Civic and I noticed a slight whining/whirring noise when it's idling in neutral with the clutch out, but the noise goes away when I push the clutch in. The noise is very slight and it doesn't sound particularly unhealthy like grinding or anything. The car drives and shifts perfectly and I can't hear that noise while I am driving, only at idle if I am really paying attention I can hear it goes away when I press the clutch, especially in my garage or against a wall. Does that sound normal or like something I should be concerned about? I'm thinking it's probably normal, but I'd appreciate your input.

Before I installed the transmission I opened it up to replace the input shaft bearing as that is a common failure on these cars, so that shouldn't be the source of the noise. The gear teeth and synchros looked perfect from what I could tell. I tried to take a video of the noise from inside the car with the hood open as I was by myself, but my phone's mic didn't really pick it up. Please forgive my ignorance as I am new to manual transmissions, this is my first one. Thanks in advance, any input is greatly appreciated!

 

[atikovi]

Did you replace the throwout bearing?

 

[cpayne5]

Throwout/release bearing. Don't worry about it unless it gets loud.

 

[Avery4]

Did you replace the throwout bearing?

Yes I did, I also replaced the pilot bearing, I used OEM Honda parts on both

 

[oggb]

It sounds like you replaced the pilot bearing, throwout bearing, and the input shaft bearing from your other posts. The bearing most likely to be causing your noise is the input shaft bearing. Bad throwout bearings typically make noise when you press on the clutch pedal. To be honest if it's a very slightly noise it could just be that you have some worn out transmission mounts and the harmonics are juuuuust right.

Slight noises are hard to diagnose. Drive it for a while and see if it gets worse is my advice.

 

[Avery4]

It sounds like you replaced the pilot bearing, throwout bearing, and the input shaft bearing from your other posts. The bearings that could be causing your noise are either the input shaft bearing or the pilot. Bad throwout bearings typically make noise when you press on the clutch pedal (because that's when the throwout bearing engages with the teeth on the pressure plate). To be honest if it's a very slightly noise it could just be that you have some worn out transmission mounts and the harmonics are juuuuust right.

Slight noises are hard to diagnose. Drive it for a while and see if it gets worse is my advice.

Thanks for the information! Yup, input shaft and pilot bearings are both new. I do have Innovative 75A polyurethane mounts, which are probably transferring more of the noise to the chassis and making it sound louder than it normally would. As slight as the noise is I likely wouldn't even hear it with stock mounts.

 

[SwampSurvivor]

The throwout bearing wouldn't whine (or be doing anything) if your foot is off the clutch in neutral. Same with the pilot bearing.

 

[samven]

I hope there is nothing wrong because my Fiesta S 5 speed has done that same thing since it was new. Quiet with the clutch in but a slight whiring noise when you let it out in neutral. I dont normally hear it except in the garage. In 70k miles and 10 years it has never gotten any louder or quieter.

 

[cpayne5]

The release bearing is in constant contact with the pressure plate fingers, but not loaded when the pedal is up. When the bearing is loaded (pedal goes down), the slight noise goes away. Most modern manual transmissions (not cable operated) operate this way.

The noise you're hearing is normal. Amazing how one's senses are heightened after performing major work on a vehicle, isn't it? I suffer from the same condition.

 

[cpayne5]

...duplicate...

 

[Avery4]

The release bearing is in constant contact with the pressure plate fingers, but not loaded when the pedal is up. When the bearing is loaded (pedal goes down), the slight noise goes away. Most modern manual transmissions (not cable operated) operate this way.

The noise you're hearing is normal. Amazing how one's senses are heightened after performing major work on a vehicle, isn't it? I suffer from the same condition.

I did not know that, I thought the release bearing was only in contact with the pressure plate when the clutch was pressed. But in either case I would think that if the noise I'm hearing was from the release bearing it would get louder when I load it by pushing the clutch instead of going away. Thanks for the information!

 

[aquariuscsm]

Every standard tranny car I've owned made a slight mechanical noise while idling with the clutch out. That's just the tranny's internals spinning. Completely normal.

 

[Avery4]

Every standard tranny car I've owned made a slight mechanical noise while idling with the clutch out. That's just the tranny's internals spinning. Completely normal.

That's what I thought, thank you! Seems normal to me, but good to hear from someone who is more experienced with manual transmissions than I am.

 

[CheezWhiz]

my theory on car noises is that everything is probably fine until the noise gets so bad that you can no longer pretend everything is fine.

 

[Lubener]

Did you replace the throwout bearing?

Throw out bearing would make noise when the clutch is disengaged (pedal pressed).

 

[SwampSurvivor]

That's what I thought, thank you! Seems normal to me, but good to hear from someone who is more experienced with manual transmissions than I am.

Every manual I've had has had it to a varying degree. My truck's transmission is relatively quiet, but I had a new Jeep with a NV3550 manual that was very noisy with the clutch out. My Focus' transmission always had a weird rattle idling in neutral.

The release bearing is in constant contact with the pressure plate fingers, but not loaded when the pedal is up. When the bearing is loaded (pedal goes down), the slight noise goes away. Most modern manual transmissions (not cable operated) operate this way.

The noise you're hearing is normal. Amazing how one's senses are heightened after performing major work on a vehicle, isn't it? I suffer from the same condition.

While it is in contact, it isn't doing anything. Both "sides" of it will be turning at the same speed.

 

[Cujet]

Normal. With the clutch out, trans in neutral, all of the parts in the transmission are spinning with the exception of the output shaft. There is no load on these parts and they can "rattle" a bit as they rotate.

The input shaft bearing on manual transmissions have been a problem on certain models for as long as cars have been made. Sometimes this can be due to low fluid levels, that don't adequately splash lubricate the input shaft bearing under low RPM use. Manufacturers strive to reduce fluid drag and keep the levels as low as practical. Other times, the bearing is simply of inadequate quality or a less robust design.

It brings to mind some engines that have camshaft failures due to extended idling. Inadequate lubrication is always the cause. Those same engines have no problems when operated at high RPM's for extended periods of time.

 

[Sveina]

It depends on the severity of the sound, but a common culprit for this kind of sound is low oil level in the trans.

 

[Avery4]

Normal. With the clutch out, trans in neutral, all of the parts in the transmission are spinning with the exception of the output shaft. There is no load on these parts and they can "rattle" a bit as they rotate.

The input shaft bearing on manual transmissions have been a problem on certain models for as long as cars have been made. Sometimes this can be due to low fluid levels, that don't adequately splash lubricate the input shaft bearing under low RPM use. Manufacturers strive to reduce fluid drag and keep the levels as low as practical. Other times, the bearing is simply of inadequate quality or a less robust design.

It brings to mind some engines that have camshaft failures due to extended idling. Inadequate lubrication is always the cause. Those same engines have no problems when operated at high RPM's for extended periods of time.

Good to know, thank you! The input shaft bearing seems to be a big problem on these cars, but I'm not sure what exactly causes the failure. The old input shaft bearing was definitely bad though, it is ridiculously loose and rough. I have heard some people suggest slightly overfilling the fluid to help prevent the failure, but that doesn't seem like a very good idea to me.

Seems like the failure is caused in part by the fact that the input shaft bearing a plastic cage that holds the balls. The cage on mine wasn't broken, but it seems common for the plastic cage to break apart. Makes me wonder why the cage is plastic other than for a marginal cost savings, seems like one of the worst possible things to cheap out on.

 

[jeepman3071]

Thanks for the information! Yup, input shaft and pilot bearings are both new. I do have Innovative 75A polyurethane mounts, which are probably transferring more of the noise to the chassis and making it sound louder than it normally would. As slight as the noise is I likely wouldn't even hear it with stock mounts.

Yep, that is likely why.