GEARBOX NOISE

[s3c chris]

Hi all.

Another query I'm afraid! When I bought my car I was able to detect a very slight noise from the gearbox and this was diagnosed as noisy first motion shaft bearings. It wasn't bad at all but definetely audible at tickover and slightly on acceleration.

As I'm (apparently) very fussy I decided to get the gearbox rebuilt and a well known specialist was entrusted with the job. Upon dismantling, the bearing carriers were seen to be scored slightly and there was no pre-load on the layshaft , both of which could have caused the noise. New bearings were fitted and the layshaft shimmed.

Unfortunately the noise is still there! Will it go away and what is acceptable? I have listened to the gearbox in my old car and it is annoyingly silent by comparison! Whilst the box was out I took the decision to replace the clutch, despite the cars low mileage of 28k. The new AP clutch is lovely and light thankfully but the biting point is right at the bottom now which is a little disconcerting. What is normal? The clutch on my previous car was replaced too and that was fine.

All comments appreciated!

Regards Chris.

[steve j]

Hi chris, my clutch has recently been replaced and it bites just above half the pedal travel, maybe yours needs bleeding. As far as the gearbox noise is concerned, could it be the propshaft u/s ? or even the c/v joints rumbling a bit, they too may need a bit of grease.

[s3c chris]

Hi.

Thanks for the reply.I too am thinking that the hydraulics need bleeding as half way seems about right, which is where the last one was.

The prop has been checked and the noise occurs when stationary so I think that can be ruled out. I am thinking the gearbox will need to be checked again but will give it a few more miles before doing this.

Regards Chris.

[Sardonicus]

s3c chris said:

Hi.

Thanks for the reply.I too am thinking that the hydraulics need bleeding as half way seems about right, which is where the last one was.

The prop has been checked and the noise occurs when stationary so I think that can be ruled out. I am thinking the gearbox will need to be checked again but will give it a few more miles before doing this.

Regards Chris.

It won't quieten down, if it's noisy somethings wrong

[ChimpOnGas]

I doubt it's air in the system but as this is super easy to check you may as well eliminate it first off by simply violently pumping the pedal, if there is air in the system a few violent pumps of the pedal will change the bite point (temporally).

Try it, it's a completely free and very quick test to prove or disprove the "air in the system" theory.

The truth is clutch bite point is dictated by many things, but given you have a new AP clutch I'd recommend double checking your hydraulic bore ratio (master and slave cylinder bore sizes).

The correct ratio is an 0.70" master cylinder working with a 1" slave cylinder, its quite common for this ratio to be altered when either the slave or master cylinder fails and gets replaced with a unit of the wrong bore size.

Its also worth making sure the clevis pin that links the clutch pedal to the master cylinder push rod fork is not worn & wasted as this is very common, alternatively it could just be an adjustment issue at the pedal (pedal stop or master cylinder push rod).

If all that checks out then a bent release arm is a possibility but normally the slave push rod will simply punch through the cheap pressed steel release arm, at which point your clutch will at best feel very odd and most probity not function at all.

Do check the hydraulic ratio (bore sizes of both cylinders), and then if they are correct check and adjust the master cylinder push rod at the pedal but don't forget to examine the clevis pin condition.

[N7GTX]

The noise may not be the gearbox but the spigot bush. It is the bush in the centre of the flywheel where the shaft from the gearbox fits. It should always be replaced when the clutch is.

http://www.powersperformance.co.uk/store/search/sp...

The noise was pronounced at idle and did not alter if the clutch pedal was pressed.

[Sardonicus]

N7GTX said:

The noise may not be the gearbox but the spigot bush. It is the bush in the centre of the flywheel where the shaft from the gearbox fits. It should always be replaced when the clutch is.

http://www.powersperformance.co.uk/store/search/sp...

The noise was pronounced at idle and did not alter if the clutch pedal was pressed.

That would have to be pretty bad to allow the input shaft to move around to that extent thus creating transmission noise but possible I'll grant you

[s3c chris]

Hi and thanks for the replies.

I am sure the noise is from the gearbox, it as a definite whirring/ gear noise. I would assume the spigot bearing was checked when the box was removed for me to take it for the rebuild. The car has only done 28K so hopefully no problems with that but I will ask.

The strange thing is, the clutch felt perfect before, it just seemed silly not to change it. Maybe I have a lesson to learn..... I'm thinking the box will need to come out again.

Regards Chris.

[N7GTX]

Sardonicus said:

N7GTX said:

The noise may not be the gearbox but the spigot bush. It is the bush in the centre of the flywheel where the shaft from the gearbox fits. It should always be replaced when the clutch is.

http://www.powersperformance.co.uk/store/search/sp...

The noise was pronounced at idle and did not alter if the clutch pedal was pressed.

That would have to be pretty bad to allow the input shaft to move around to that extent thus creating transmission noise but possible I'll grant you

It happened to mine after the rebuild. The noise was really only heard at idle. Sounded just like a gearbox bearing or bush was worn. Pressing the clutch made no difference. In neutral and revving the engine and it was still there. On the road the engine and exhaust noise masked it so it wasn't obvious.
It went back, new bush fitted and the difference in the cabin noise was quite a lot.
Remember your DI Transits? They all had spigot bush noise!

[Sardonicus]

N7GTX said:

It happened to mine after the rebuild. The noise was really only heard at idle. Sounded just like a gearbox bearing or bush was worn. Pressing the clutch made no difference. In neutral and revving the engine and it was still there. On the road the engine and exhaust noise masked it so it wasn't obvious.
It went back, new bush fitted and the difference in the cabin noise was quite a lot.
Remember your DI Transits? They all had spigot bush noise!

Thats interesting thanks

Edited by Sardonicus on Monday 9th November 09:32

[ChimpOnGas]

Sardonicus said:

Thats interesting thanks

Edited by Sardonicus on Monday 9th November 09:32

Oh no, there goes another £18 towards my S-10 gearbox mod and lighter clutch job

Oh well, "In for a penny, in for a pound".... or lots of pounds as the case may be

[Sardonicus]

ChimpOnGas said:

Oh no, there goes another £18 towards my S-10 gearbox mod and lighter clutch job

Oh well, "In for a penny, in for a pound".... or lots of pounds as the case may be

Well I run out of time in the end but I am going to get mine machined larger to take the Sierra Cos needle/pin bearing always for that solid bush idea was ste and it is when the box comes out next its getting the treatment my local machine shop said a cheap piece of piss to machine proper

[ChimpOnGas]

Sardonicus said:

ChimpOnGas said:

Oh no, there goes another £18 towards my S-10 gearbox mod and lighter clutch job

Oh well, "In for a penny, in for a pound".... or lots of pounds as the case may be

Well I run out of time in the end but I am going to get mine machined larger to take the Sierra Cos needle/pin bearing always for that solid bush idea was ste and it is when the box comes out next its getting the treatment my local machine shop said a cheap piece of piss to machine proper

Looks nice Simon

But I've just gone for a new brass jobbie, a plane bush is crude... but also effective for the job in my experience.

I've never seen a plane bush spit a needle roller either

Arguments either way me thinks

[Sardonicus]

ChimpOnGas said:

Looks nice Simon

But I've just gone for a new brass jobbie, a plane bush is crude... but also effective for the job in my experience.

I've never seen a plane bush spit a needle roller either

Arguments either way me thinks

And I have never seen a spit needle on a pilot/spigot bearing and I've had an awful lot of Fords with em I just think its crude so for the cost involved its going

[ChimpOnGas]

Sardonicus said:

ChimpOnGas said:

Looks nice Simon

But I've just gone for a new brass jobbie, a plane bush is crude... but also effective for the job in my experience.

I've never seen a plane bush spit a needle roller either

Arguments either way me thinks

And I have never seen a spit needle on a pilot/spigot bearing and I've had an awful lot of Fords with em I just think its crude so for the cost involved its going

Fair play mate, go for it

As we know the job of the spigot bearing is just a supporting role, but it just occurred to me I have experienced a strange (part screech part grumble) noise when everything gets heat soaked and I suffer my slightly baulky gear selection issue.

First I thought the noise was the belt, then the water pump or alternator grumbling, but when that all checked out I simply assumed the noise was a combination of a slightly noisy release bearing and the fractionally dragging clutch

But I guess that little noise could just as easily be the spigot bearing?

The guy that fitted my Helix is a local one man band clutch specialist, he's a decent type that's built his long standing business on reputation. There's no doubt he knows his way around most clutch jobs but I have to say he wasn't familiar with the Chimaera.

I told him about the gear linkage, then showed him pictures of it so he could get is head around the thing, I even did a partial interior strip up top so he could see for himself.

But on his first attempt he still bent the linkage a bit

The gear shift was nasty so I had to ask him to take the box out again and to straiten the linkage, after that the shift was fine cold and warm but with the trans tunnel became heat soaked the 1st and 2ng gear baulking issue appeared. The truth is because the problem came with the clutch installation it could just be the Helix dragging, or it could be the bent linkage again, it could even be a bit of both

Then there was the time a year or so later after the Helix was fitted when the slave push rod came off the release arm because I bent release arm very slightly!!! This was all my fault as I was messing around with clutch push rod lengths trying to get the Helix to feel a bit nicer, the bent release arm eventually meant the box and engine had to be split at the bell housing yet again. By this time I wouldn't be at all surprised if the spigot bush had taken a few knocks, one thing is for sure the release bearing became a bit noisy from that point on

Honestly, I really should do these things myself, but with no ramp and just a small inspection pit at my disposal I simply can't face it

So you can see why this time I'm so determined the job is going to be right, whatever happens I know I'll have a much lighter clutch than my current left leg muscle building Helix.

But with the addition of the S-10 tail housing and all the other parts I'm hoping the shift issues when hot will be eliminated too, and with any luck my T5 may even shift even better than it did from new?

This time I'll put my faith in Lloyds because they've never let me down yet, so at least I've got the experts on my side, not to mention a stack of parts and upgrades that (on paper at least) should all work together to give us the very best chance of success.

Fingers crossed hey

Dave.

Edited by ChimpOnGas on Monday 9th November 16:45