??? Vibrations whilst driving

[moranor@axis]

im picking up a heavy vibration from the gearbox in 4th under hard acceleration sometimes...
also the one offramp i take often has some very rough rumple strips on it when i go over them i have my hand on the gear leaver ready to change down it feels like the gears are grinding... im not sure this is normal?

this all point to the gearbox in my head :thinking: i just dont want to spend any more till i know what the problem is...

 

[Sankekur]

Maybe the gearbox mounts aren't properly fastened.

 

[moranor@axis]

Maybe the gearbox mounts aren't properly fastened.

ill have a look at that...
do you mean:

or:

because not all the bolt holes line up with the engine so not all the bolts could be fitted im hoping its not that because if it is i will have to put the 5 speed back to solve the problem...

 

[Sankekur]

Was actually thinking of the first one, but now that you mention it the second might also cause problems, how are the bolts spaced? I am thinking if they are evenly spaced there should be less of a chance that it might cause vibration. But I think it would sill be worthwhile to check the bolts to see if they have been properly fastened.

 

[moranor@axis]

ill cheack all when under

they are evenly spaced and the mech that did the convertion did not think i should worry about it at all but there is always the small chance...

 

[moranor@axis]

right finally found the cause of all this (i hope ) the e90 six speed gear box has about a 6mm offset so i need to make up the gap...

there are two options:

get an e90 flywheel or
get a single mass flywheel made with the same offset as the e90

im going to price them then weigh up my options both have advantages and disadvantages

 

[DonovanPorter]

any progress here?

 

[moranor@axis]

well i found a guy that can make me a flywheel but im thinking of using the e90 flywheel because it will be better for normal driving...
i can always get one made later if i want...

but the way i look at it the lighter flywheel will only make sense once my car is also lighter... also i can lighten up the rest of my drivelines without any negative effects (except on my wallet) so ill do that 1st before the flywheel...

 

[DonovanPorter]

cool

 

[moranor@axis]

im going to be seriously pissed if this is not the problem

oh btw the e90 flywheel is about 500g lighter than the e46 but i doubt i will feel any differance...

 

[DonovanPorter]

mabe you never know ?
also stating to get a vibration round about 4000rpm not to sure even where to start checking

 

[moranor@axis]

what car you have?

 

[DonovanPorter]

1999 e46 318i

 

[moranor@axis]

flywheel vibrations normally happen at low rpm like 2000...

maybe describe what you have

 

[DonovanPorter]

o here goes

in any gear from +-3800rpm i get i vibration which comes from the rear of the car , wich increases with the speed sounds a bit like a dronning sound

 

[moranor@axis]

is the droning the same in every gear? does it happen on acceleration or deceleration?

 

[DonovanPorter]

only on acceleration apon changing gears it goes away and its in every gear

 

[moranor@axis]

im not sure but i did read that the output bearings on the diff can do this... also does the noise go when you push the clutch down?

 

[DonovanPorter]

ja i does

 

[moranor@axis]

sounds like the exact opposite of what i have :thinking: i will be sure to let you know if changing the flywheel on my car fixes my problem...

have you taken your car to any mech and asked them what they think it is? my car has been to every driveline/bmw specialist in town and none can work it out... but you have standard drive lines so it should be easier on your car...

i have even contemplated getting a camera to strap to the bottom of my car so i can try see this vibration and try work out what is going on...

maybe someone else can shed some light on your problem...