14 replies to this topic

[james4563]

I've noticed a couple of times a noise while in neutral. It's loudest by the rear passenger wheel, very noticeable if you were to be outside the car by the back. Like a tapping/chatter/knocking kind of noise. Goes away completely when I press the clutch pedal down.

Having had similar noise on a previous car I suspect something like clutch release bearing?  Is there anything else that makes this kind of noise? Or is it normal for this setup?

 

Seems strange something would be damaged as the car has covered about 5K miles since having stage 4 mods done. Which included clutch ( i would hope with new release bearing ).

 

[Nev]

The F23 slave cylinder is fickle. Check your invoice + warranty.

[gaffer1986]

First thing I thought was clutch release bearing.

[Mattias]

Do you have light weight flywheel?

If so it's just vibrations going in to the gearbox in a more noticeable way due to less mass to damp the vibrations. Some hear this on oem setup also it's a from gearbox to gearbox issue...

 

I got the same symptoms even with a new clutch release bearing. There is a thread on here somewhere where gearbox bearings etc. are ruled out, also google lightweight flywheel noise

[james4563]

It has a lightened flywheel yeah. Mattias, does yours make a lot of noise on overrun too. Like in gear when you lift off? I've got quite a lot of rattle from what I can only assume is the gearbox. Having only just bought the car in hoping the gearbox isn't tired...

[Mattias]

I'll think it makes some sound on lift off but I can check tomorrow. You should also check your upper engine mounts, when those break the gear box may start to sound, mine sounded like a straight cut gearbox on acceleration.

 

The weak point of these gearboxes are the synchro rings if it's abused, I've been running 400hp and 480nm for a while now and it still holds together.

 

Only other issue I've had is a 4th gear whine but it has almost dissiperad after changing  to motul racing oil and adding MCR, but it's good to know that it will be a little harder to shift with cold box but it just takes a couple of minutes for it to start shifting like a dream no matter how much it's pushed on track. I can easily throw in a new gear in a blink of an eye

 

Motul: https://www.motul.co...f[viscosity]=59

MCR: http://www.x1r.uk.co...d=801013-100006

 

 

[james4563]

I'll think it makes some sound on lift off but I can check tomorrow. You should also check your upper engine mounts, when those break the gear box may start to sound, mine sounded like a straight cut gearbox on acceleration.

 

The weak point of these gearboxes are the synchro rings if it's abused, I've been running 400hp and 480nm for a while now and it still holds together.

 

Only other issue I've had is a 4th gear whine but it has almost dissiperad after changing  to motul racing oil and adding MCR, but it's good to know that it will be a little harder to shift with cold box but it just takes a couple of minutes for it to start shifting like a dream no matter how much it's pushed on track. I can easily throw in a new gear in a blink of an eye

 

Motul: https://www.motul.co...f[viscosity]=59

MCR: http://www.x1r.uk.co...d=801013-100006

 

 

 

Do you have the F23 gearbox? Not the 6 speed conversion.

 

Courtney told me that the F23 shouldn't make any noise at all with a lightened flywheel, especially on idle. They said as well that if the noise goes away when I push the clutch down then it's probably a worn bearing in the gearbox input shaft. Obviously they cannot be sure on that without doing work on the box and stripping it down. 

[siztenboots]

clutch friction disc centre springs

[Mattias]

 

I'll think it makes some sound on lift off but I can check tomorrow. You should also check your upper engine mounts, when those break the gear box may start to sound, mine sounded like a straight cut gearbox on acceleration.

 

The weak point of these gearboxes are the synchro rings if it's abused, I've been running 400hp and 480nm for a while now and it still holds together.

 

Only other issue I've had is a 4th gear whine but it has almost dissiperad after changing  to motul racing oil and adding MCR, but it's good to know that it will be a little harder to shift with cold box but it just takes a couple of minutes for it to start shifting like a dream no matter how much it's pushed on track. I can easily throw in a new gear in a blink of an eye

 

Motul: https://www.motul.co...f[viscosity]=59

MCR: http://www.x1r.uk.co...d=801013-100006

 

 

 

Do you have the F23 gearbox? Not the 6 speed conversion.

 

Courtney told me that the F23 shouldn't make any noise at all with a lightened flywheel, especially on idle. They said as well that if the noise goes away when I push the clutch down then it's probably a worn bearing in the gearbox input shaft. Obviously they cannot be sure on that without doing work on the box and stripping it down. 

 

 

First off I do also hear some noise on lift off but I have to concentrate since my car is noisy in general.

 

I have the F23

 

So what your saying is that Courtney want to send you a big fat bill?

 

Jokes aside, if you do some search on here you will find that someone, can't remember who, went down the route of changing bearings but the noise remained.

 

This is a known issue at GM that becomes more noticeable when fitting a lightened flywheel.

Read here on Mechanical faults, noise 2: https://en.wikipedia...23_transmission

 

I started notice the noise right after fitting my new flywheel, clutch, pressure plate and release bearing, but after researching  I came to the conclusion that the solution is to live with it or fit oem flywheel.

 

What happens is that a lightweight flywheel doesn't damp the harmonics/rpm fluctuation pulses as a heavy flywheel does. And when in neutral the input shaft rotates and creates the noise, when clutch is engaged the shaft doesn't rotate hence no noise.

Edited by Mattias, 03 August 2016 - 11:25 AM.

[siztenboots]

some of this is also the map, "active load shock absorption" , which I have adjusted in the map packs as part of RaceMode

[tibby]

Same over here... Also 400hp and 520nm on a Regelin alu flywheel with Helix 4puck.(Fully rebuild with new internals and LSD) F23 box has done 13000km since rebuild described as above. Rattles from day 1. No problems ...... I use in the winter OEM Opel/Vauxhall gearbox oil for smooth cold changes and summertime Castrol Syntrans 75W90 Fill F23 box with 2 litres oil. grtz

Edited by tibby, 03 August 2016 - 03:55 PM.

[Mattias]

some of this is also the map, "active load shock absorption" , which I have adjusted in the map packs as part of RaceMode

 

But isn't that only when applying/releasing throttle?

[james4563]

I changed my gearbox oil this weekend, noise is now much improved, and generally quieter overall. I drained out only 1.5 liters, left it draining for over 30 minutes. I also jacked the car up from each side to make sure I could drain as much as possible.

Then removed the level plug and put the car flat to fill until oil dribbled from the level plug, as per the VX manual. It took 1.9 liters until anything came from the level plug, I had bought 2 x 1 liter OEM GM gearbox oil from Vauxhall so I just poured the last 100ml in anyway.

 

Interestingly Courtney told me the box only takes 1.5 liters, and that there is no level check plug on the F23 gearbox. They were the last people to do anything relating to gearbox oil on this car to the best of my knowledge. Make of that what you will.

Seems the box was under filled by about 400ml, which I feel is quite a lot. Hope nothing has been subjected to damage from that, there was no metal in the oil I drained so fingers crossed!

Edited by james4563, 09 August 2016 - 10:21 AM.

[The Batman]

Common knowledge I thought to put 2L in after draining it Silly courtenays

[tibby]

https://en.wikipedia...23_transmission