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+--- Thread: Excessive transmission noise in car. (/showthread.php?tid=2834)
RE: Excessive transmission noise in car. - spannerman - 25-05-2019
Is the sliding joint on propshaft free
To slide in and out ?
RE: Excessive transmission noise in car. - Roger - 25-05-2019
Garry,
Just looked in Woodrow, it does mention, “Fit propellor shaft” to gearbox, although that could be taken as a generic description of the whole shaft rather than just the longer bit.
Roger
RE: Excessive transmission noise in car. - Chris KC - 25-05-2019
(25-05-2019, 02:51 PM)Graham Honnor Wrote: [quote='Roger' pid='29526' dateline='1558771017']
I don't doubt for one minute that this is correct, but would it be possible for someone to explain to me why the long part of the shaft has to be this way round please.
I haven't heard this before and wondered what the reasoning is. Would it be to do with the amount that the axle goes up and down compared to the gearbox?
Graham, a so-called 'constant velocity' joint is not precisely so, in fact it speeds up and slows down a little during each revolution. By aligning the front and rear joints in this way, the errors in one joint cancel out the errors in the other. Failing to do so may result in vibration and premature failure.
RE: Excessive transmission noise in car. - Reckless Rat - 25-05-2019
For what its worth the HS propshaft on my RP has always had the sliding joint at the gearbox end, and its been fitted that way for the past 35 years. Fit it the other way and you' d have to grease it from underneath. The greasing point has a blanking plug to avoid the handbrake issue.
RE: Excessive transmission noise in car. - GK5268 - 26-05-2019
The sliding joint should be at the gearbox end, this being the farthest point from the actual axle movement.
RE: Excessive transmission noise in car. - spannerman - 26-05-2019
I would say gearbox end , but look
At oiling chart is it the other way
Because axle has a mounting
Just after the axle tube ? The
Otherthing it would be less
Mass for suspension to move
Just a thought?
RE: Excessive transmission noise in car. - Tony Press - 27-05-2019
(25-05-2019, 06:53 PM)Chris KC Wrote:The 1930's Austin Seven tail shaft universal joints are Hook Joints which give the changing rotation speed needing cancellation as shown.(25-05-2019, 02:51 PM)Graham Honnor Wrote:(25-05-2019, 08:56 AM)Roger Wrote: I don't doubt for one minute that this is correct, but would it be possible for someone to explain to me why the long part of the shaft has to be this way round please.Graham, a so-called 'constant velocity' joint is not precisely so, in fact it speeds up and slows down a little during each revolution. By aligning the front and rear joints in this way, the errors in one joint cancel out the errors in the other. Failing to do so may result in vibration and premature failure.
I haven't heard this before and wondered what the reasoning is. Would it be to do with the amount that the axle goes up and down compared to the gearbox?
The later development of the Constant Velocity (CV) joint results in a non variable transition and doesn't need the 'cancellation'.
Earlier Austin Seven tail shafts are fitted with the rear Pot type joint with a similar action to the Hook joint- the front Fabric front 'UJ', because it acts like a CV joint doesn't cancel out the rear joint changes in rotational speed.
None of this explains your noisy car.
RE: Excessive transmission noise in car. - Roger - 28-05-2019
http://www.austin7.org/Technical%20Articles/Propshaft%20Howl/
I have just found this article above, also the thread below.
http://www.austinsevenfriends.co.uk/forum/showthread.php?tid=328&pid=2444&highlight=Propshaft+fitting#pid2444
Roger
RE: Excessive transmission noise in car. - Charles Levien - 29-05-2019
Might be worth checking that the center rear sump bolt is not touching the flywheel.
Just a thought.
Charles
RE: Excessive transmission noise in car. - Roger - 29-05-2019
Thanks Charles,
No, checked that one too, it’s not an easy noise to describe.
Looking under the bonnet the engine sounds ok, maybe not as quiet as some well built A7 engines.
Inside the car it does sound very”Rough” I assumed it was the diff at first as it is acceptably quiet on the over run. I fitted a new driveshaft, no better.
All I have left is gearbox and engine now, then I will have to start at the back again and check everything.
Roger