Gearbox Noise

[mikehume]

Hi,

My car is a Fabia VRS 2005 - 41k

I've noticed this last week that when starting gentle acceleration (50-70mph over take on the motorway) in fifth or sixth I experience a vibration/resonance/grinding noise from what sounds like the front passenger side. It doesn't happen in any other gears, even when really low in the rev range. In fifth and sixth this noise will gradually disappear from about 2000 revs onwards. Could this be an indication of gearbox problems? I'm sure I've heard somewhere this could be an indication of low gearbox oil, can anyone confirm?

Thanks in advance,

Mike.

[raf tom]

i had a vibration from mine when going from second to third also after long trips i noticed that there was rather a lot of engine movement at idle with the bonnet up, i took it to a dealer and they said that it was the dual mass flywheel. the flywheel was replaced under warenty and the vibration / humming noise dissaperaed. however the large ammount of movement hasent.

i think that the cause of the excess movement is being caused by worn engine mount bushes this is prematurely caused by the imballence of the engine due to the flywheel failure.

if you are fortunate enought to still be covered by warrenty then get it replaced and that should solve the problem. if not then take it to a dealer and get them to have a look at it if they say that it needs replacing then i would advise replacing the standard dual mass flywheel with a solid flywheel, this would not be much more than the standard unit and would also remove the fault from possibly reocouring.

As to the low gearbox oil level i am not sure that this would cause the noise.

[MoggyTech]

The six speed gearbox uses two output shafts, shaft 1 has gear 1 to 4, shaft 2 has 5th and 6th gear and the reverse idler gear. More likely to be gearbox than DMF, as DMF will knock at specific torque no matter what gear your in.

Simple test, get up to speed where the noise occurs, come off the throttle and dip the clutch. If the noise remains or reduces slightly, it will be 2nd output shaft bearings. If the noise reduces a lot, it will be 5th or 6th gear bearings.

Test two, in neutral, rev engine to the revs where the fault occurs, if no noise it's the gearbox, if noise happens, it's something on the engine (alternator pulley/aircon pump/aux drive belt tensioner etc)

I wouldn't recommend fitting a single mass flyhweel as you loose the torque damping effect of the DMF, and it can damage the gearbox, and also increase idle chatter in the gearbox due to torque spikes.

A simple gearbox oil top up or even oil change may cure it.

Edited 18 July, 2009 by MoggyTech

[ric04vrs]

it could just be the fact that the OP is using the torque of the engine below 2k revs and the DMF is making the usual noise and vibration which occurs when laboured at low revs