Mansfield
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| posted on 12/1/07 at 07:34 PM |
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What exactly makes a gearbox whine?
I have pronounced whine under certain conditions (lots of left lock accelerating hard in 1st or 2nd) in my tin top (1995 petrol 406).
I dont expect anyone on here to diagnose this fault without driving the car, but before I can it would help me to understand the mechanical aspect of
this noise. Is it some sort of bearing noise or some sort of cogs being forced toghter noise or someting else?
I could guess gearbox/diff/driveshaft supoort bearing myself but that wont help me fix it. The car will be a write off if I cant do it myself but I
need to understand the problem first.
What makes that bloody noise?
Thanks David.
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Jon Ison
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| posted on 12/1/07 at 07:36 PM |
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possibly a wheel bearing ?
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Mansfield
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| posted on 12/1/07 at 07:41 PM |
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Jon, I had not considered that.
I can accelerate as hard as I like in a straight line or turning right.
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smart51
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| posted on 12/1/07 at 07:45 PM |
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Gearbox whine on a stright cut gear is caused by the teeth engaging. Each time a tooth from one gear touches a tooth from the other, it makes a
click. Once you get up some speed, the clicks are so frequent that you hear it as a whine. Its the noise you get in reverse in a car.
Helically cut gears don't whine because the rub against each other diagonnaly rather than hitting each other head on. They are less efficient
because of this and wear more but no-one seems to care. Bike engines have straght cut gears as performance is more important than noise.
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cossiebri
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| posted on 12/1/07 at 07:46 PM |
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Are you sure it's not coming from the...Passenger seat, I tend to get a whine from there 
iirc pug(also read citroen) gearboxes are renown for there noise, we have a 307 and that tends to whine on occasion(?)
also had a brand new picasso diesel and was told 'they all do it sir!'
If it doesn't fit MODIFY it!!
Cheers BriF
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stevec
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| posted on 12/1/07 at 07:52 PM |
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If it is the box I have a brand new one
Steve.
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rusty nuts
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| posted on 12/1/07 at 08:30 PM |
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Wheel bearing would normally show up at higher speeds as a whine that would get worse when one lock is applied and quieten when on the other lock
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Mansfield
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| posted on 12/1/07 at 08:34 PM |
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I didn't want to turn this into a 'what wrong with my car?' question because I didn't think anyone would be able to diagnose
it without driving and seeing it.
Its hard to get away from that though so I will try and describe the symptoms more accurately.
Accelerate hard out of a junction on near full lock left - horrible whine. Nurse it out of junction on hard lock left - no problem. Accelerate
straight or hard lock right - no problem. Noise sounds in middle & front of car. It was not like this 3 months ago, I have owned the car 3
years.
I think I have an engine mount (vibration at 2000rpm and a knock power on/off without careful clutch control) the way out - 406 is notorious for top
cambelt end mount working loose but this is tight. Maybe a lower mount is to blame here, this may make the engine move and displace the drive shaft
or it may not.
I am wondering if its the diff or the bearing support on the long offside driveshaft that could cause this. The offside front tyre is a lot newer
than the nearside - I think this puts extra load on the 'problem' but of course, I may be wrong.
Sorry for the delay in replying, my brother-in-law has called telling me he has noisy brakes on his Vectra. It has taken me 2 years to start cutting
Locost tubes and now I have to spend my time fixing tin tops.
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Mansfield
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| posted on 12/1/07 at 08:36 PM |
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Rusty Nuts- high speed no problem, think I can discount the wheel bearing then its only inthe conditions described in my last post.
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t.j.
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| posted on 12/1/07 at 08:47 PM |
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Sounds like a problem in your diff.
But first check out your engine mounts and check if some mountings of your wishbones aren't worn. (cause maybe you're wheel is simply
hitting your mud-guard or something)
So: first EYES open and check
Then try to localise trying on turning wheels to simulate drivingconditions.
Grtz Theo
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macnab
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| posted on 12/1/07 at 09:02 PM |
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before pulling it to bits...have a look at the engine mount rubbers.
Have they sagged?? If so then a lot of gearbox noise can then get transmited into the car making it seem that you gearbox is knackered. My older
Bluebird has this problem, sounds like an old jet engine. One day I might even bother to change them over...
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jollygreengiant
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| posted on 12/1/07 at 09:10 PM |
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quote:
Originally posted by t.j.
Sounds like a problem in your diff.
But first check out your engine mounts and check if some mountings of your wishbones aren't worn. (cause maybe you're wheel is simply
hitting your mud-guard or something)
So: first EYES open and check
Then try to localise trying on turning wheels to simulate drivingconditions.
Grtz Theo
Or a bottom arm mounting bush so badly worn that its allowing the wheel to pull its self into/onto wheel arch cowlings/other item.
Beware of the Goldfish in the tulip mines. The ONLY defence against them is smoking peanut butter sandwiches.
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macnab
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| posted on 13/1/07 at 08:17 PM |
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ooh nasty...
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ChrisGamlin
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| posted on 13/1/07 at 09:19 PM |
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Older Pugs like the 205 / 309 were notorious at knackering driveshafts, I don't know what the 406 is like with this but a knackered driveshaft
would make noise at the times you describe, although is usually more of a pronounced knock than a whine
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