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CLUTCH or Gearbox damaged?
bikecarbfred - 4/8/15 at 08:46 PM

I've searched everywhere on the forums but cannot find anyone with the exact same problems.
They are similar but not exact which could change the outcome of the problem.

Getting more of a flap rather than knock noise whilst driving in gear. Increases with rpm

1) Does not do it in 1st gear - does it in 2nd,3rd, 4th & 5th. Tries my best to hear it in 1st but exhaust to loud over 2500 rpm
2) It's not that loud yet. does it most in low rpm's - torque.Whilst driving.


I put it in 1st and went to around 4000rpm to build the speed to make sure it does not make a noise in 1st. Quickly change to 3rd gear. Flap......flap...flap...flap..flap

Noise goes away when pressing clutch completely.

3) standing till. No noise.
4) standing still . clutch in : no noise
4) In gear while drivigng on de-acelleration makes the noise too.


What you guys reckon:

Driveshaft, throw out bearing, gearbox input shaft, differential or something else

The performance of the car has not changed. gear changes are smooth, pulls the same.
Thanks guys. Puzzle this is.

madteg - 4/8/15 at 08:58 PM

What engine and box

rusty nuts - 4/8/15 at 08:59 PM

Go on , give us a clue , what car, engine etc

bikecarbfred - 4/8/15 at 09:14 PM

quote:
Originally posted by rusty nuts
Go on , give us a clue , what car, engine etc


Silly me. all that jibber jabber and don't put what car. sorry
1.4 Polo 16v 1997

85 Box

ReMan - 4/8/15 at 09:22 PM

"Getting more of a flap rather than knock noise whilst driving in gear. Increases with rpm "
Does it increase with sped too, to just enine speed?

bikecarbfred - 4/8/15 at 09:31 PM

quote:
Originally posted by ReMan
"Getting more of a flap rather than knock noise whilst driving in gear. Increases with rpm "
Does it increase with sped too, to just enine speed?



When it's in gear and speed is going up the flapping gets quicker. but also the rpm is increasing so it's hard to relate it to speed as if I am going 40mph then push the clutch pedal in and stick it in to neutral the noise instantly goes away yet i'm still doing 40mph.

[Edited on 4/8/15 by bikecarbfred]

coyoteboy - 4/8/15 at 10:57 PM

But if you stick at 40 and use two different gears to see if the flap happens faster in 3rd or 4th it will tell you if it's RPM based or wheel speed based.

MikeRJ - 5/8/15 at 05:07 PM

The gearboxes are extremely weak on this era of Polos and failure is common. However, it's usually a bearing problem causing a loud whining noise rather than the noise you describe.

How fast is the noise e.g. once per wheel rotation? If so it could be a broken tooth on the diff ring gear or possibly a CV joint on it's way out.

bikecarbfred - 5/8/15 at 10:05 PM

@Mike RJ Yes it's once per wheel.

@ coyoteboy It was hard to test whether it was speed or rpm related. I took it out tonight underpark tesco and I have to say I hear it very lightly in 1st gear and that is probably because of the speed is slow.

As the speed went up the the nose went faster.

This noise is like a flap but more of a scratch flap. No whining, the gear box seems so smooth and the power is effortless.

I wish it is inner CV Joint. But how can it be a inner CV joint if when you press the clutch the noise goes away.


P.s At 50 MPH the road noise/wind cancel the noise out 90% - It also seems torque related. When underload - the low torque you can just feel it more.

I found this from another website for someone else who had a similar problem:
"I'd go along with the CV joint suggestion, it goes quiet when you dip the clutch because the driveshafts do not then transmit any torque. "

[Edited on 5/8/15 by bikecarbfred]

MikeRJ - 6/8/15 at 07:14 AM

quote:
Originally posted by bikecarbfred

I wish it is inner CV Joint. But how can it be a inner CV joint if when you press the clutch the noise goes away.


Because you are removing all the torque through the drivetrain.

bikecarbfred - 7/8/15 at 07:37 PM

Well it is not input shaft bearing because there is no noise in Neutral.
I don't think it's the gears because theres no whining and it's smooth.

It either output/differential within the gearbox / inner cv joint
or clutch bearing.

How could clutch bearing be ruled out?

Also tomorrow going to be running the car supported so there will be no weight on the wheels. Will see if this effects the noise.

I will be safe. I use wooden pallets to support the car.

mark chandler - 8/8/15 at 06:43 AM

Not a lot of point in running it with the wheels in the air as no load.

Check outer cv's by reversing slowly on full lock and listen for them clicking, before getting radical and changing anything cut the bands on the shaft ends of the cv boots, prise open a gap and work some grease into the joints then close up with cable ties, if this cures it you know you have a joint on its way out but with fresh grease it may still outlive the car.

You also want to change the gearbox oil while under there

Regards Mark


[Edited on 8/8/15 by mark chandler]

bikecarbfred - 8/8/15 at 10:15 AM

2)No click or clunk when turning.
3)By hand I move driver side wheel back and forward and can hear a clunk. Don't know if this is usual to get a play in the transmission or not.
5) No grease on any CV rubber boots - loads of oily grease on under driver side wheel well but must have drove over a oily puddle.


4) Car on stands and running, it makes the noise even with no load on tyres.

I am sure it is just doing it in 2,nd, 3rd, 4th, & 5th. Not looking good.

coyoteboy - 8/8/15 at 10:40 AM

Where abouts are you?

bikecarbfred - 8/8/15 at 11:23 AM

England S.yorks

p.s it is 100% doing rotation noise in all gears.

Having had it on the supports and the noise I can describe is as follows:

It's like have some metal stuck in brakes and it scrapes the disc every so often with the rotation. so maybe flap is not the best word to describe. it's more kr....kur..... kur.... kur

Inbetween a flap noise and a scrape noise.


[Edited on 8/8/15 by bikecarbfred]

K13JOB - 8/8/15 at 05:39 PM

quote:

It's like have some metal stuck in brakes and it scrapes the disc every so often with the rotation. so maybe flap is not the best word to describe. it's more kr....kur..... kur.... kur

Inbetween a flap noise and a scrape noise.



Perhaps that is where you should look, are the discs running true and free.

bikecarbfred - 8/8/15 at 07:24 PM

quote:
Originally posted by K13JOB
quote:

It's like have some metal stuck in brakes and it scrapes the disc every so often with the rotation. so maybe flap is not the best word to describe. it's more kr....kur..... kur.... kur

Inbetween a flap noise and a scrape noise.



Perhaps that is where you should look, are the discs running true and free.


But when pressing clutch the noise goes away so got to rule out brakes and disc.

Also got to rule out Input shaft because no noise in Neutral when clutch is engaged?

bikecarbfred - 9/8/15 at 03:49 PM

https://www.youtube.com/watch?v=HAmt2YtQCak

This is not my car but can someone tell me if this noise is expected?
I know you always get a slight transmission play in the box.


Manually rotating brake disc back and forward.
But when I had the car in the air I was getting this alot.
Infact when I had the driver side wheel on the ground the passenger side was up and the noise was immense like a knock noise. A loud knock noise. This is probably because with the driver side wheel on the ground I was not allowing that to move.

When I got the drivers side wheel up so both wheels are in the air. The noise was similar to that in the video.

regards.