[Healeys] Mystery noise - Update

Sat Aug 22 20:54:13 MDT 2020

Well, then it is rotational for sure, not a bearing that is failing but perhaps already failed, perhaps allowing the O/D annulus to scrape the surrounding housing...though it did not sound like steel on aluminum to me. You have moved the noise from rear to midway.. perhaps if you haven't, check for a failed motor mount and the crank pulley scraping the cross member??  DP

On August 22, 2020, at 6:46 PM, Roger Grace via Healeys <healeys at autox.team.net> wrote:

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Not a lot of progress...

Brake cable is well clear of propshaft and securely clipped.

Universal U joint/spline phasing is correct.

Been doing lots of listening with stethoscope.

With propshaft disconnected, am able hear noise in 2nd or 4th when slipping clutch (reduces speed)

Assume is the same noise and less distinct because of the engine noise.

Not nearly as distinct as when shaft is connected and rear wheels freewheeling in neutral and engine off.

Loudest area seems to be rear GB casing near rear bearing.

This still does not sound like a bearing to my ears ?

Plan to try to get a 2nd expert opinion with younger ears !

rg

----- Original Message -----
From: David Nock <healeydoc at gmail.com>
To: Roger Grace <roggrace at telus.net>, 'healeylist' <healeys at autox.team.net>
Sent: Thu, 20 Aug 2020 12:47:51 -0600 (MDT)
Subject: Re: [Healeys] Mystery noise

Drive shaft hitting the handbrake cable when the car is jacked up. Probably 
will go away when sitting on the ground.

David 
Nock
healeydoc at sbcglobal.net
209 948 
8767
www.britishcarspecialists.com

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From:Roger Grace via Healeys

Sent: Thursday, August 20, 2020 10:27 AM

To:'healeylist'

Subject: [Healeys] Mystery noise

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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