Hello CX members...been a long time member but this my first post as I've been able to find answers amongst all the knowledge here up to this point. I've searched and searched but nothing is coming up that points me in the direction that correlates to the noise I'm hearing at the time I'm hearing it. I have what sounds like a bearing whine/squeal in all gears on a 6 speed manual, '15 pro4x, 130k (bought new, no mods). It started off in a couple gears as a cyclical wee wee wee.... but now happens in all gears under load (on the gas) between 2000-3000 rpm, in both 2wd and 4wd. It will also happen when I'm in a low enough gear and can coast downhill where the rpms get to the "zone". Anything below 2k quite as a church mouse, approaching 3k and over slowly goes away. No noise in nuetral at any speed. Push in clutch and it disappears immediately. All this points to some bearing seeing a load in the drivetrain and not liking it I think. I've changed the final drive front u-joint and went so far as to open the boot on the rear cv joint and heavily lubed it to see if the noise calms down - no change. I've changed the rear wheel bearings. New oil in the rear diff and the transmission - no change. It shifts like the day I got it, stays in gear, no vibration in the stick, accelerates fine. I'm at a loss other than just going in and changing pilot, throw-out, input, rear diff front bearing? etc.....it's loud now when it happens so the time has come to ask for help. Any thoughts would be appreciated.
Need help with high pitched whine/sqeal diagnosis
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Input Shaft Bearing noise???
So my truck is back, but my friend who did my timing belt noticed a new sound that happens in Neutral and at low gears when the clutch pedal is RELEASED. It's a cross between a chirp and a whirring. It goes away when the truck warms up and drives for a while (about 20 mi) mostly. AFAICT, the...
www.clubxterra.org
Jian Tao is having a similar issue.
But his is a first Gen.
Sounds the opposite to me. I have no noise in neutral (clutch in or out) and it's only prevalent when it warms up and driving at the rpms I mentioned.Input Shaft Bearing noise???
So my truck is back, but my friend who did my timing belt noticed a new sound that happens in Neutral and at low gears when the clutch pedal is RELEASED. It's a cross between a chirp and a whirring. It goes away when the truck warms up and drives for a while (about 20 mi) mostly. AFAICT, the...
Jian Tao is having a similar issue.
But his is a first Gen.
got it
Yes the sounds speeds up to the point where it almost disappears above a certain rpm. U-joint has been changed and the CV joint on the rear of the driveshaft has been checked.
Thank you for the suggestion on the driveshaft center support bearing. edit....although there isn't a support bearing on the driveshaft itself. ujoint at the front connection and cv joint at the rear into the rear diff.
Sorry I must not have been reading quite right this morning.
Have you gotten under the truck and done a bench press on the drive shaft, to see if there is any slack in the output shaft or going into rear differential?
Have you gotten under the truck and done a bench press on the drive shaft, to see if there is any slack in the output shaft or going into rear differential?
Yup been under it and rotated the shaft and pushed on it. Have not gotten into a bench press position and pushed...assuming I should be feeling for radial slop at the bearing on either end, transfer case output and rear diff input.
My plan for this weekend to try to isolate where the noise is coming from which I think is either going to be one of those 2 bearings. I'm going to mount a gopro next to each one and take it for a drive. Hoping the audio will tell me by which position is the loudest. Will report back with any findings.
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Radial slop won't always show up in bad bearings. If fine dirt or corrosion have made their way in they can make noise for a long time before they are worn enough to have noticeable slop. The debris causes minor binding and or friction that results in noise. Of course, it would generally be a mistake to ignore it at the initial stages.
The most puzzling thing about this is that the sound is so high pitched and so loud that it sounds like a dry shaft running thru a dry sleeve bearing or a brake pad wear tab rubbing a rotor but only at a very specific rpm range. I've watched and listened to so many "bad bearing" videos on youtube and this sounds nothing like those bad bearings. Hope the different camera locations can pin point the source and then I'll go from there.
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Mine went...
e........e..........e.........e........e.......e.......e......e......e.....e.....e.....e.....e....e....e....e....e...e...e...e..e..e..e..e..e..e..e..e.e.e.e.
The spaces between squeaks being shorter as the vehicle sped up, but there was only noise under load.
e........e..........e.........e........e.......e.......e......e......e.....e.....e.....e.....e....e....e....e....e...e...e...e..e..e..e..e..e..e..e..e.e.e.e.
The spaces between squeaks being shorter as the vehicle sped up, but there was only noise under load.
yup that is it exactly but there is no center support bearing on the drive shaft so I'm still at a loss
Everything is pointing to the pilot bearing. The noise is rpm related not speed related. It only happens after the vehicle warms up and is driven hard. RPM related means transmission and forward in the drive train, anything behind the transmission would only be speed related, warm vehicle means the viscosity of oil is at its lowest. A friend who has rebuilt many a manual transmission was consulted and taken for a test ride and his diagnosis is pilot. He is adamant that nothing rear of the transmission could be making the noise. He went so far as to suggest changing the 75w-85 out to a heavier weight oil in the transmission so when the vehicle heats up the oil doesn’t get as viscous and retains its ability to better lubricate the pilot. This would only be a temporary “fix” until I gather the parts to do a rebuild but there is no imminent need just drive her easy.
I’m on board with his reasoning. Hope this helps others with similar mystery noises.
I’m on board with his reasoning. Hope this helps others with similar mystery noises.
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I'm going to assume that you mean input shaft bearing.
The pilot bearing/pilot bushing is located in a little hole in the end of the crankshaft and is used as a guide for the input shaft when the transmission is connected to the engine. It also prevents the shaft from having too much play once everything is together. It is usually (as is the case in the Xterra) made of cintered bronze that is impregnated with oil at the factory. This bushing/bearing is installed dry (as it is self lubricating) and does not come into contact with any oils or lubricants (unless you have a really bad rear main seal leak).
There are a lot of things in a manual transmission system that can make a squeaking noise. A throw out bearing that doesn't release fully, a bent finger on the pressure plate, a slave cylinder that isn't retracting fully and results in the throw out bearing being in partial contact with the pressure plate fingers.
Keep in mind that a part that rotates at the speed of the engine (or crankshaft and input shaft) is going to squeak at a rate of 16.7 times per second at 1000 RPM (a little over idle and 50 times per second at 3000 RPM). I'm not convinced that the human ear can pick out individual squeaks at that rate. It would be more of a constant whine.
That said, you could try what your friend suggests and see if it clears up your issue.
Have you bled your clutch lines recently? If not, you might also give that a try to make sure that the slave doesn't have moisture built up inside it. Water tends to gather in the slave and it will warm up as the vehicle is run. This will cause it to expand (or even boil) and actuate the piston in the slave. This could push the throwout bearing forward enough so that it is making slight contact with the pressure plate. Nothing to lose by doing a flush. It's routine maintenance anyways.
The pilot bearing/pilot bushing is located in a little hole in the end of the crankshaft and is used as a guide for the input shaft when the transmission is connected to the engine. It also prevents the shaft from having too much play once everything is together. It is usually (as is the case in the Xterra) made of cintered bronze that is impregnated with oil at the factory. This bushing/bearing is installed dry (as it is self lubricating) and does not come into contact with any oils or lubricants (unless you have a really bad rear main seal leak).
There are a lot of things in a manual transmission system that can make a squeaking noise. A throw out bearing that doesn't release fully, a bent finger on the pressure plate, a slave cylinder that isn't retracting fully and results in the throw out bearing being in partial contact with the pressure plate fingers.
Keep in mind that a part that rotates at the speed of the engine (or crankshaft and input shaft) is going to squeak at a rate of 16.7 times per second at 1000 RPM (a little over idle and 50 times per second at 3000 RPM). I'm not convinced that the human ear can pick out individual squeaks at that rate. It would be more of a constant whine.
That said, you could try what your friend suggests and see if it clears up your issue.
Have you bled your clutch lines recently? If not, you might also give that a try to make sure that the slave doesn't have moisture built up inside it. Water tends to gather in the slave and it will warm up as the vehicle is run. This will cause it to expand (or even boil) and actuate the piston in the slave. This could push the throwout bearing forward enough so that it is making slight contact with the pressure plate. Nothing to lose by doing a flush. It's routine maintenance anyways.
Thank you for this! Will def add this to the process. Yes pilot bushing. In fact the noise is exactly what a dry shaft in a dry sleeve bushing would sound like.
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The only time that the input shaft spins in the pilot bushing is when the clutch pedal is depressed. The rest of the time the crank shaft and input shaft are locked together by the clutch and rotating at the same speed. ie. The pilot bushing is also spinning at the same speed as the input shaft. The only way it would be making noise with the clutch pedal released is if the clutch is slipping like a mofo.
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