Noise Reduction

[JCH]

Whilst I fully appreciate that the Terrano produces a great deal of Engine noise,is there anyone who has attempted a noise reduction exercise,and if so what were the results.
The noise from my engine is acceptable until I go into fifth gear,then it is very noisy.
Engine runs very well indeed and I can achieve excellent top speeds when required.
Please let me know.

[macabethiel]

Originally Posted by JCH

Whilst I fully appreciate that the Terrano produces a great deal of Engine noise,is there anyone who has attempted a noise reduction exercise,and if so what were the results.
The noise from my engine is acceptable until I go into fifth gear,then it is very noisy.
Engine runs very well indeed and I can achieve excellent top speeds when required.
Please let me know.

The noise level should drop when you go from 4th to 5th gear are you sure its not gearbox noise ? On modern 5 speed gearboxes 4th is a direct gear ratio of 1:1 but when you go to 5th the ratio will drop probably to something like 1:0.90 the actual gear ratios are in your handbook under technical data.

This means that that one of the gear shafts (layshaft) is rotating relative to the main shaft and that might be inducing a gear noise under the increased torque at the reduced r.p.m. some sort of bearing problem in the gearbox most likely. Have you changed the gearbox oil recently and checked for debris?

[AlexD333]

Suspect Gbox too, but do you have padding on the bonnet?

the later models were scrapped of it to save nissan a few quid

[JCH]

I bow to your knowledge, however It does not sound like gearbox noise, more like coming directly from the engine.
The gearbox oil has not been changed since I bought it two years ago.Should I feel any difference if I get it done.The gears themselves are very smooth.
Incidentally the main noise from 5th gear is only when my foot uses the accelerator.For example when zipping along a motorway with foot off the pedal the noise significantly reduces.Its like a clanking noise !!!!

[theron]

I get a bit of a whining noise from the transfer box while in 5th. Does the noise get worse if you push gently sideways on the transfer box gear lever?

[Banshee]

Originally Posted by JCH

I bow to your knowledge, however It does not sound like gearbox noise, more like coming directly from the engine.
The gearbox oil has not been changed since I bought it two years ago.Should I feel any difference if I get it done.The gears themselves are very smooth.
Incidentally the main noise from 5th gear is only when my foot uses the accelerator.For example when zipping along a motorway with foot off the pedal the noise significantly reduces.Its like a clanking noise !!!!

Best thing I can suggest here mate is that you get someone to record from the inside of the car on a phone so we can hear it as you change through the gears, to those tuned in to the 2.7TDi engine tones we may be able to pick up on what you are hearing

[rustic]

So you have had the vehicle for two years, has the noise got worse over those two years, or are you just more aware of it and want to quieten it down?

Clearly if there is no major change, and you have covered lots of miles in those two years, then you can hopefully eliminate any gear box noises.

If the noise is getting worse month by month, then you can look into mechanical issues.

The exhaust bracket on the gearbox can loosen, and cause vibration.
The under engine tray bolts can loosen, and that can sound like a machine gun.
The front flexi joint on the exhaust can fail and give excessive noise.
But linking those to only fifth gear is unlikely.

Now, quite a few members use low ash mineral two stoke oil in the ratio of 200:1
This has been known to quieten the engine down, and improve the burn process, and some say, it also is said to reduce emissions.

I use it on my Td, and I have to say, it appears quieter.
Rustic