[Healeys] Mystery noise

[David P]

Pretty sure dave Nock nailed it..

On 8/20/2020 3:01 PM, Roger Grace via Healeys wrote:
> M,
> Thank you and always respect your experienced input.
> Did you perhaps listen to the file ?
> OK will try this again; but when cut engine without prop shaft it 
> stops abruptly.
> Will try to listen with engine running.
> Also I have have the impression that it is when torque direction is 
> from wheels spinning and trying to overrun the transmission - like 
> coasting.
> Will report back.
> Tkx
> rg
>
> ----- Original Message -----
> From: Michael Salter <michaelsalter at gmail.com>
> To: Roger Grace <roggrace at telus.net>
> Cc: healeylist <healeys at autox.team.net>
> Sent: Thu, 20 Aug 2020 13:05:23 -0600 (MDT)
> Subject: Re: [Healeys] Mystery noise
>
> Hi Roger, you say "Disconnecting prop shaft to isolate diff not 
> possible as need the inertia of the rear wheels to produce the pulsing."
> I think that is unlikely and would look into that more closely.
> If you can get access to a "Chassis Ear" that would probably help a lot.
>
> M
>
>
> On Thu., Aug. 20, 2020, 1:28 p.m. Roger Grace via Healeys, 
> <healeys at autox.team.net <mailto:healeys at autox.team.net>> wrote:
>
>     AH people - fighting a noise in my BJ8 that may or may not be serious.
>     Reluctant to tear out the tranny unnecessarily and then to find it
>     was something simple !
>     Notice it at low speed (probably exists at driving speed but too
>     much wind and engine
>     noise) if shift to neutral and cut ignition to minimize engine and
>     exhaust noise.
>     Noise is pulsating - like a tire with a bad spot but seems to be at
>     prop shaft speed.
>     At first thought that it was at wheel speed and from R side.
>     So changed out the R wheel bearing.
>     No improvement
>     Then while looking below noted that universals had some play.
>     So changed out both universals.
>     Rear brakes not dragging and no binding of wheels.
>     No improvement.
>     Did listening on hoist with others listening too. Consensus was
>     that there was a noise at rear OD area as well as the pulsating one.
>
>     So pulled annulus in situ and replaced both rear bearings. Quieter
>     but still the pulsating noise while coasting in N.
>     Sound file enclosed is a road test from about 15 MPH then shift to
>     N and cut engine. Tunnel cover off.
>
>     Able to replicate noise with engine on axle stands but not by
>     turning a rear wheel by hand or with an e motor.
>
>     Noise does appear to come from transmission.
>
>     To verify is not diff removed one of the rear seats and noise
>     doesn't appear to be coming from diff area.
>     Disconnecting prop shaft to isolate diff not possible as need the
>     inertia of the rear wheels to produce the pulsing.
>     About 5k miles ago I changed out the larger OD front bearing
>     (sourced from
>     Moss ... ?) in the OD.
>     OD works fine and transmission shifts and works OK without unusual
>     noises.
>
>     The pulsating/cyclical nature of the noise baffles me and not
>     consistent
>     with a bearing failure ?
>
>     Given that it occurs in neutral with no gears meshing it surely is
>     not a bad gear tooth etc.
>     OD not engaged so it is locked so not likely there.
>     Removed gearbox top cover and did inspection - nothing obvious.
>     So to my mind this only leaves the GB rear bearing ?
>     Or maybe a broken circlip or thrust washer and probably on main
>     shaft external to gearbox ?
>     or half shaft ?
>
>     Any comments/thoughts appreciated from the more experienced among us.
>     Tkx
>     rg
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>     Is
>
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>
>
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