What is this sound on some buses and coaches

[heart-of-wessex]

Hello all,

I've noticed this sound on Bath's Wright's Eclipse's before, but recently out on a Rail Replacement I noticed it on a few Volvo coaches and one of the DAF ones too.

I've got a short video where you can hear this 'whine' on this DAF VanHool L444 SGB

https://www.youtube.com/watch?v=CLsESN_rbnc

The engine is rather quiet, but I could hear this rather clear, the sound dips down on a gear change and rises up again, something to do with the gearbox I assume? If so, what gear system is it?


Any help appreciated!

James.

 

[Dhassell]

I believe it's just something to do with the gearbox and transmission
another good example is on optare solos,

 

[J-2739]

I believe it's just something to do with the gearbox and transmission
another good example is on optare solos,

The whine on the Solos are absolutely freakish.

 

[GusB]

Hello all,

I've noticed this sound on Bath's Wright's Eclipse's before, but recently out on a Rail Replacement I noticed it on a few Volvo coaches and one of the DAF ones too.

I've got a short video where you can hear this 'whine' on this DAF VanHool L444 SGB

https://www.youtube.com/watch?v=CLsESN_rbnc

The engine is rather quiet, but I could hear this rather clear, the sound dips down on a gear change and rises up again, something to do with the gearbox I assume? If so, what gear system is it?


Any help appreciated!

James.

Sounds to me like a ZF gearbox.

 

[Citistar]

I suggest it sounds like transmission whine - could be any number of things. The differential and gearbox are both prime candidates.

I believe the "chicka-waaaah" whine on the original Solos was caused by reasonance from the gearbox along the driveshaft, which is why later ones (and none of the slimline ones) suffer with it. The Wilts & Dorset R and S-reg ones were astonishing, particularly in later life, whereas my 2002 example doesn't make much noise at all from the transmission.