ChrisS
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| posted on 9/4/08 at 11:22 AM |
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Transmision Noise
I know ive asked about transmission noise before, but this is a little more specific. im quite happy to live with the general clonky bike gear change
thing, but having just completed my first 12 legal road miles, i just want to clarify this once again.
On decelaration, the drone/vibration type of noise coming from what i can make out is the diff/driveshafts seems to be excessive. As soon as the power
is back on all seems smooth.
I used an overhauled 3.38 sierra push in driveshaft Diff from KitBits and i overhauled the driveshafts myself, new cv boots and grease etc,
I just cant help thinking something is loose or knackered from the noise that comes from back there. Ive checked what i can but wondered how much
noise to expect from this type of setup.
Is this normal, should i just stop worrying?
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Hellfire
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| posted on 9/4/08 at 11:30 AM |
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Without actually listening to the noise, it's quite difficult to say. Our diff certainly doesn't drone or vibrate on deceleration. Can you
not buy/borrow a diff and try a different one out. If nothing else, it will confirm whether the diff is the cause of the noise or not.
Phil
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nick205
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| posted on 9/4/08 at 11:34 AM |
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Not a BEC, but my car clonks and whines a lot, especially in traffic and on overrun.
Remember that the diff is solidly mounted to the chassis, right next to your left buttock and the prop shaft is effectively in the car with you.
I'd say stick with it and you'll get used to it - do you wear a helmet? It cuts down on the noise a fair bit 
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paublo999
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| posted on 9/4/08 at 11:55 AM |
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check your propshaft alignment. I assume you have a centre bearing and a two piece prop? When trying to minimise the same issues on my Westfield I was
told that the UJ's should only be moving in one plane.... I hope this makes sense..
My fireblade gearbox output is higher and to the right of my tunnel. I spaced the centre bearing up by about an inch and it certainly helped with the
noises/droning as you suggest on deceleration.... I also had my prop balanced and turned into a TRT but this didnt help with the symptoms you are
asking about - well on my car it didnt... 
My car still makes some awfull sounding noises at really low speeds and on taking my foot off the throttle (acceleration and constant speed was ok) at
anything above 80mph (on the track of course...)
I do wonder if a better/tighter diff e.g. an ATB unit instead of my open English Mark II escort diff would also help.
Cheers
Paul.
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Bigheppy
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| posted on 9/4/08 at 12:51 PM |
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Cheak for oil in the diff
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paublo999
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| posted on 9/4/08 at 01:09 PM |
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my first diff just got hotter without oil...
dont bother considering these diff additivies either - it just made the oil more runny and let the diff make even more noise...
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ChrisS
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| posted on 9/4/08 at 01:13 PM |
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quote:
Originally posted by Bigheppy
Cheak for oil in the diff
I checked it and its definately got oil in it. I remember filling it.
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BearingKits
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| posted on 9/4/08 at 02:18 PM |
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Normally noise that varies with the throttle is caused by the pinion moving in and out slightly.
This can be worn bearings, loose pinion nut (internal nut on a Sierra diff) or CWP out of mesh a little.
This is just the normal most common cause of a noise/drone.
Vibration is unlikely to be the diff, this will normally be rotating parts like the propshaft but i have even experienced tyres that give the same
type of noise (after changing 3 axles!)
www.Bearingkits.co.uk
Gearbox, Differential and Axle rebuild parts.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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richard thomas
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| posted on 9/4/08 at 02:46 PM |
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Lobro's.
Happened to me - couldn't see any great play in anything back there, changed the lobro's - job's a good 'un.
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ChrisS
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| posted on 9/4/08 at 02:55 PM |
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quote:
Originally posted by richard thomas
Lobro's.
Arent Lobros the bolt on types?
Im using push fit drive shafts.
Just spoken to a nice bloke and road and race transmissions in sevenoaks who has siad that if i take the car to him he will have a listen and advise
what the best course of action is. Cant say fairer than that.
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richard thomas
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| posted on 10/4/08 at 04:51 PM |
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I'm guessing that even if they are push in,they are still CV joints and work the same. I tought my old ones were fine, surprising how much even
a little amount of play makes a noise.
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motorcycle_mayhem
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| posted on 11/4/08 at 08:48 AM |
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This isn't going to be an easy one to diagnose until something is clearly worn or breaks... keep checking. Seriously though, I get all sorts of
vibes, noise from the transmission, not helped by the self-destructing oil losing reverse box. Booting the crap out of it and getting one of those
Peltor ear-muff equipped helmets are my solution. If the MSA weren't so akward and insisting that the car went backwards under it's own
power, I'd have done a centre bearing mod.
Diff noise is quite distinctive - my tow vehicle (LWB Transit with lightweight axle) has a trashed diff., grinder sounds around corners, howl, whine -
really needs ear defenders (seriously). I NEED to find some bearing kits (or something) very quickly before it explodes... I think you'd know if
it was the diff!
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