Possible Gearbox Noise?

Gday all,

Lucas here, just saying gday and have brought another Nav but this time a D40.

I have a question, 06 spanish 6 spd manual, there is a noticeable noise from the gearbox but when i depress the clutch pedal (stop gearbox spining) the noise goes away and the engine is silent.

is this likely to be a noise gearbox? bearing or is this the clutch related issue?

sounds to me like a gearbox. I am just heading out to check the oil level and condition. it was just serviced and nothing was mentioned about it.

is this noise normal or am i being paranoid? i should mention that it shifts smooth and the noise doesnt seem to get louder or change with vehicle speed or engine rpm..

cheers

I reckon mine does this too, and I have the same year STX.

Release bearing in the clutch.

Sounds opposite to how you think it would work - put your foot on the clutch, and the release bearing is under more load.

But for whatever reason, they make most noise when under load.

The gearbox in the D40 is a pretty heavy duty piece of kit.

I had a release bearing on my last 4wd that was noisy when the clutch wasn't depressed. But it was a chirping noise. The easiest way to check this is to see if the noise goes away when you just lightly push on the clutch pedal, if you have to fully depress the clutch before the noise goes away, then it is the gearbox.

Even if the gearbox is a little bit noisy, it may not be an issue, manual gearboxes always become a little noisy with age. The D40 gearboxes are not known to give trouble, so I wouldn't panic about it.

I don't have any experience with dual mass flywheels, but it is also possible that that may be making noise under some circumstances ? Maybe someone who has had more experience with them ?

Clutch Thrust race bearing

Thanks guys for your feedback! After going out and testing it again, I've noticed that the sound disappears with only a slight depressing of the clutch pedal.

However, if I am driving along and take foot off accelerator, it makes the noise while coasting. I'm suspecting clutch is on the way out anyway (it's stock as far as I know - 113,000km), but would this noise still be occurring while only coasting?

Clutch Thrust race bearing

Cool, thanks Nathan! Needed to do the clutch anyway.

Navara might translate in Spanish to "cash guzzler" the way this thing is treating me.

However, the D22 was much less maintenance.. (ZD30)

I'm going to go for Exceedy SMFW with heavy duty I reckon.

yeah my ZD30 D22 didnt get a cent spent on it other then the service costs and it was going strong with 370k on it.

I have read a few (not all) that have developed a vibration from going with the HD clutch, might pay to research which ones did and did not do it??

Oh right, yeah I did some research a while ago as to what to replace it with but I'll have to go more thorough to find this vibration issue. Thanks mate!

From what I can understand the the O.P. Lucas said.

there is a noticeable noise from the gearbox but when i depress the clutch pedal (stop gearbox spining) the noise goes away and the engine is silent.

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So from what I can gather it's rollover noise in the gearbox. Theoretically the thrust bearing is only turning when your foot is on the clutch (depressed) gearbox not rolling over. In this case it goes away under these circumstances. So I find it would be unlikely to be the thrust bearing.

If your D40 is fitted with a single mass flywheel there will be more rollover noise in the gearbox and slightly more vibration as the DMF's take away a lot of torsional vibration and associated noise that comes with this.

I know my Thai built Nav has the SMF and compared to the DMF's it is noisier so if the Gearbox oil is ok and it drives fine I would not stress to much about it.

The other likely cause of rollover noise is the spigot bearing or in the case of Nissan the spigot bush is a bit dry. For some reason Nissan prefer to use a bush over a bearing.

Hey guys, I've had my SMF and HD Exedy clutch done before the chrissy break, and I was hoping this noise would be gone. However it is not, I would have thought the issue would be fixed with a new clutch (or at least when it was all pulled out). Thoughts?

Amos said:

Hey guys, I've had my SMF and HD Exedy clutch done before the chrissy break, and I was hoping this noise would be gone. However it is not, I would have thought the issue would be fixed with a new clutch (or at least when it was all pulled out). Thoughts?

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Well, if it's rollover noise in the gearbox then changing the clutch will make no difference. Can you describe the noise, rollover noise is 'grumbly', gearboxes will also whine while driving, a worn gearbox will usually whine in all gears except 5th where there is no side-loading on the gears.

Thanks Kernels. It's probably more of a whine than grumbly. It happens when idling out of gear and disappears when you depress the clutch. And also when driving along in any of the 6 gears and letting off the accelerator pedal and coasting. In fact going over a bumpy road with light pressure on the accelerator makes it happen between bumps when foot pressure bumps off the pedal.

Amos said:

Thanks Kernels. It's probably more of a whine than grumbly. It happens when idling out of gear and disappears when you depress the clutch. And also when driving along in any of the 6 gears and letting off the accelerator pedal and coasting. In fact going over a bumpy road with light pressure on the accelerator makes it happen between bumps when foot pressure bumps off the pedal.

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So, if I understand you correctly, the whine happens when the gearbox is turning without load. When you are driving up a hill with constant speed there is no whine? but run down the other side of the hill using engine braking and you get the whine ?

If that is the case, then it's very likely that one of the bearings on the input shaft (there are 2 or 3) is worn.

If it makes the whine while stationary in neutral, then it must be on the input shaft of the gearbox, the output shaft, transfer case and rear diff are not turning at that point.

I assume the thrust bearing was changed with the clutch ? To make the noise go away, must you fully depress the clutch, or does it go away when you just put a little bit of pressure on the clutch pedal ?

Yep you're spot on there. I just went and tested and with only pressing the clutch pedal in at the top it goes away - it doesn't require fully pressing the clutch to get rid of the sound.

I'm assuming the thrust bearing was changed with the clutch too.

Going by what you are saying, it might be the bearings on the input shaft of the gearbox? Is this a big job do you know?

Thanks for your help too!

Amos said:

Yep you're spot on there. I just went and tested and with only pressing the clutch pedal in at the top it goes away - it doesn't require fully pressing the clutch to get rid of the sound.

I'm assuming the thrust bearing was changed with the clutch too.

Going by what you are saying, it might be the bearings on the input shaft of the gearbox? Is this a big job do you know?

Thanks for your help too!

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OK, to make the sound go away, are you pressing the clutch far enough down to make the gearbox stop spinning or are you just touching the pedal to take up the free-play ?

If you have to press the clutch a reasonable distance down and gearbox stops spinning, then it's the gearbox. If you just touch the pedal softly and the sound goes away then it is the thrust bearing.

I just checked this arvo, the noise goes away when i press the clutch in a reasonable amount, probably a bit over half way in.

Amos said:

I just checked this arvo, the noise goes away when i press the clutch in a reasonable amount, probably a bit over half way in.

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Yup, definitely gearbox then, have you checked the oil level ?

I got the same thing exedy smf kit and does the same thing ,its called gearbox chatter
Talked to a few gearbox mobs and ist nothing to worry bout ,Lucas oil thickner
quiets it down a bit but makes the gears hard to get in while cold .If you bring the revs up in nuteral the noise goes away. Nothing you can do about it so I learned to live with it is it not causing any damage . Just sounds like a old school diesel.