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Author: Subject: Name that transmission noise!
striker-euan

posted on 3/11/13 at 08:52 PM Reply With Quote
Name that transmission noise!

Not quite as catchy as name that tune, but can anyone identify what issues my transmission may have resulting in these noises

audio here - new link
or
same audio - original link

The car has a type 9 gearbox, quaife atb, solidly mounted diff and was driven on a fairly smooth road at less than 50mph.

45 seconds in is where the interesting noises are most obvious - trailing throttle produces a loud whine. It is quietest under acceleration, no difference when cornering.

Local mechanic says there is play in 1 driveshaft and play in the diff.

I'm fairly sure the engine alignment relative to the diff is like "A" here...



Any advice before I send the diff off to a specialist would be welcomed, plus much kudos for diagnosis just from an mp3!

[Edited on 4/11/13 by striker-euan]

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40inches

posted on 3/11/13 at 09:04 PM Reply With Quote
Wow! You bugged my MK! That is exactly the noise mine makes, under the same conditions. Mine actually sounds worse in reality
I have taken the propshaft off to check the UJ's and phasing, and am 99% convinced that it's the diff, have one ready to go in.






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jacko

posted on 3/11/13 at 09:04 PM Reply With Quote
No link working for me
Sorry

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jacko

posted on 3/11/13 at 09:42 PM Reply With Quote
How can i get to here this link / nose as mine makes some odd noses i have also blamed the diff
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40inches

posted on 3/11/13 at 11:17 PM Reply With Quote
Click on the link, click on "download" in the centre of the screen, listen to it using Media player etc;






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MakeEverything

posted on 4/11/13 at 09:01 AM Reply With Quote
quote:
Originally posted by 40inches
Click on the link, click on "download" in the centre of the screen, listen to it using Media player etc;


Link Clicked, but;

"Sorry, you can't view or download this file at this time.

Too many users have viewed or downloaded this file recently. Please try accessing the file again later. If the file you are trying to access is particularly large or is shared with many people, it may take up to 24 hours to be able to view or download the file. If you still can't access a file after 24 hours, contact your domain administrator."





Kindest Regards,
Richard.

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adithorp

posted on 4/11/13 at 09:20 AM Reply With Quote
Engine/diff alignment is better as B however A would cause a vibration if anything and not a whine.

Diffs do whine but normally you don't hear it as it's absorbed by the rubber mountings. Solid mount as in most kits and you do hear it, especialy on over-run. How does it compare to other kits you've been in?





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40inches

posted on 4/11/13 at 09:38 AM Reply With Quote
It isn't so much the diff whine as the grinding/chattering/knocking on the overrun
Your right, it doesn't play any more.

[Edited on 4-11-13 by 40inches]






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striker-euan

posted on 4/11/13 at 01:07 PM Reply With Quote
I'm kind of new to the kit car world so I don't have much to compare it to. It is noiser than the couple of caterhams I've been in and the local garage (who deal with various kit cars) reckon it is definitely unusually noisy. They were surprised I drive it without a helmet.


I'll see about hosting the audio file elsewhere

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40inches

posted on 4/11/13 at 01:20 PM Reply With Quote
quote:
Originally posted by striker-euan
I'm kind of new to the kit car world so I don't have much to compare it to. It is noiser than the couple of caterhams I've been in and the local garage (who deal with various kit cars) reckon it is definitely unusually noisy. They were surprised I drive it without a helmet.


I'll see about hosting the audio file elsewhere


Definitely not normal, mine sounds as though the diff is breaking up
I am fitting a screen so I don't have to wear a helmet.






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striker-euan

posted on 4/11/13 at 08:37 PM Reply With Quote
new link here
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prawnabie

posted on 4/11/13 at 09:13 PM Reply With Quote
There is usually a collapsible spacer on the pinion to set the preload - these can compress more over time, introducing backlash and giving a knocking noise when off and on the load pedal. I know a few people who have used the spacer to set the correct amount of preload, dismantle the diff and machine up a solid spacer to the same dimensions - having no collapsible part in to so it never compresses over time.

Shaun

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striker-euan

posted on 4/11/13 at 09:41 PM Reply With Quote
OK, that is good to know. That could account for the diff backlash then.

It doesn't sound like that explains the chattering/grinding when off throttle though.

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prawnabie

posted on 4/11/13 at 10:06 PM Reply With Quote
Perhaps the spacer is that compressed, the pinion is running on the crown wheel in the wrong position or rubbing on the casing?
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striker-euan

posted on 18/11/13 at 10:17 PM Reply With Quote
More experimentation shows similar noise in any gear for the same road (& prop) speed.
40mph to 60mph seems particularly bad.
Deceleration in neutral is a fair bit quieter than in-gear.

Time to send the diff off to a specialist I think.

40inches - please let me know whether a diff change solved your noise issues.

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ashg

posted on 18/11/13 at 11:45 PM Reply With Quote
sounds like a bit of crown wheel pinion mesh misalignment coupled with a noisy bearing. time for a rebuild me thinks. out of interest what oil are you running in it as my diff was much quieter when i put fords diff oil in compared to the comma stuff of the same spec that i used when i built the car.





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striker-euan

posted on 19/11/13 at 06:52 PM Reply With Quote
no idea what oil is in the diff at the moment, but I've got some genuine ford diff oil ready to go in after it gets a check up.
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40inches

posted on 19/11/13 at 08:58 PM Reply With Quote
"40inches - please let me know whether a diff change solved your noise issues."


I won't be able to tell you until March, about the time I get it back on the road.
What I can say is, that the replacement diff I have has no, or very little, backlash and feels very smooth when I turn the input shaft.
Whereas the old one has around 15 degree back lash, measured on the prop, and feels very notchy and rough.






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maurici

posted on 3/9/14 at 07:10 AM Reply With Quote
and... at the end?

Mine is doing the same after transmission rebuilding (fitting direct kit without reverse). Was suffering a lot of vibration with quife reverse's but not that noise. Right now wit the straight transmission without quife's is noising a lot.

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jeffw

posted on 3/9/14 at 07:25 AM Reply With Quote
who rebuilt the diff?






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simonrh

posted on 3/9/14 at 09:32 AM Reply With Quote
I have spent a lot of time p1ssing about with much, much, much smaller diffs where you can shim the crown wheel and pinion interference in 0.1mm intervals. which can take it from a rough running dog to a buttery smooth peach just by adjusting the engagement in tiny amounts.

Presumably with a helical cut crown and pinion and free play in the pinion spacer the pinion can move up and down the input to the diff on the overrun and cause agro?

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