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Clunking Gearbox Noise Under Load

350 Views 10 Replies 7 Participants Last post by  wolfman
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We recently investigated a clunking gearbox noise under load and found this.


A broken diff gear

To drive the car did not sound too bad until you tried to accelerate hard.

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hopefully this is one off


was it clunking when already in gear?
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QUOTE(wolfman @ 14 Dec 2009, 03:27 PM) <{POST_SNAPBACK}>We recently investigated a clunking gearbox noise under load and found this.


A broken diff gear

To drive the car did not sound too bad until you tried to accelerate hard.



so THATS where my spyrograph wheel went!
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QUOTE(vladSTer @ 14 Dec 2009, 04:00 PM) <{POST_SNAPBACK}>hopefully this is one off


was it clunking when already in gear?

If driven with a 'light throttle' the noise was not apparent as the teeth continued to mesh normally somehow? - if you floored it it the diff started banging as the teeth missed/jumped out of mesh.

The magnet in the bottom of the box was also a large mass of metal filings
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What mileage had the car done and how old was it? (warranty?)
QUOTE(robbyvrs @ 14 Dec 2009, 06:33 PM) <{POST_SNAPBACK}>What mileage had the car done and how old was it? (warranty?)

38K - and the car is driven quite hard - we have also recently replaced the front wishbone bushes and a O/S drive shaft on this car.
was this a heavily moded car Gary? strange to hear of a failed gear wheel on an
?
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why do you think it failed Gary? Metal fatigue or gearbox abuse ?
QUOTE(PHILJB @ 14 Dec 2009, 06:41 PM) <{POST_SNAPBACK}>was this a heavily moded car Gary? strange to hear of a failed gear wheel on an
?

The car was standard - I suspect that the customer had allowed a wheel to 'spin up' on a slippy surface and then driven onto a grippy surface.

This can 'shock' the diff teeth - I experienced this on my rally cars when coming off a loose surface back onto tarmac
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