Excessive transmission noise in car.

[Howard Wright]

Hi Roger

Another possibility is the clutch thrust bearing?  Try oiling and see if the noise changes?

Howard

["Slack Alice" Simon]

Half shaft pinions rubbing on diff casing because ground too far up tapers?

Starter pinion not disengaged?

Gear cluster moved in 'box so two gears touching that shouldn't be?

( I have no idea whether that is possible!)

Run down a hill with clutch out/engine off/in & out of gear/propshaft disconnected altogether.

[Roger]

Simon,

Half shaft pinions rubbing on diff casing because ground too far up tapers?
I am sure that I checked for this on reassembly and it was ok.

Starter pinion not disengaged?
This would be heard even when car stationary and engine running, but all is quiet then.

Gear cluster moved in 'box so two gears touching that shouldn't be?
Not sure about this one but would it be there on all four gears or just two from same shaft?

The last one, not too sure how this one works.

From all the replies so far I have lots to do over the weekend.

Thanks again all for the answers.

Roger

[Ruairidh Dunford]

Are the brake back plates touching the drum as it rotates?

[Bob Culver]

Compared with many other older makes the synchro box is well made and reliable. Many other common makes utilised plain splined washers to separate the mainshft gears and these disastrously fail. Many other makes strip gears (Morris 1000) and/or pit early. Mile for mile, and esp considering use, Sevens last very well. I have replaced utterly failed bearings in 1970s cars at a fraction of Seven mileage. Even when heavily pitted 1st gear remains robust. 
Main problem  seems to be ridged 1st/3rd shaft bearing surfaces and loose synchro cones, neither of which commonly strand.
The drive shaft is not original. It may have been fabricated. Is there travel in the splined part? Yolks phased?
Even poor synchro is a huge convenience as double declutching does not have to be super precise.
Significant serious problems often produce metal dust in the oil (as does unimportant pitting).
I am not sure if it is possible with Sevens but if poking about in gearbox with lid off and interlock removed, beware to not release the synchro balls.

[Chris KC]

Based purely on the description of the sound, I would suggest you are probably looking for something which is rubbing against a panel of some sort. All good ideas here, but transmissions etc tend to whine and shriek rather than 'grate'.
The first thing I would do is crawl around underneath and look for signs of rotating parts with insufficient clearance to body (bearing in mind this may change when there's weight in the car). Are the rear wheels rubbing against the body or wings for example?
The fact that it's a steady noise when driving is perhaps your biggest clue - if it doesn't rise and fall with engine speed and sounds the same in all gears then begin your search from propshaft rearwards.
Then it's a process of elimination, work your way through the suggestions starting with easiest first until you can satisfy yourself that each is or is not the cause. For example take the starter off completely, bump start the car and if the noise is still there then it's not the starter. I've forgotten who said it but it's certainly true that sounds are transmitted through the structure and you can't always tell where they are coming from.

[JonE]

Roger, perhaps a friend with a cameraphone and a facebook account could record a bit of the action for you so it would be evidence to help people narrow down your search?... (I've always though a collection of archived "sounds" would be an fabulous thing for people like me learning Sevens.)

[Mark McKibbin]

Hi Roger,
Can you tell us what your renovation involved and I assume the noise was not there before? The noise is only when the car moves? and does it change with the road speed or the engine speed?

Cheers

Mark

[Roger]

Mark,
The car was “Just a box of bits” when I started, many parts were not even for an RP.
If I just push the car in neutral no rubbing  brakes or tyres against body etc. type of noise.
The sound is similar through each gear but appears higher pitched as speed increases.
All sync gearbox has not been stripped but performs ok.
This morning took Hardy spicer shaft off, compared to one I had as spare, the splines were much worse, the splines could be rotated more than I think is good.
The spare is much better fit so will swap tonight and try tomorrow.
Will drain gearbox next and look for swarf  in oil!

Thanks for your input

Roger

[Mark McKibbin]

Roger,

Before you pull too much apart, have you travelled in a similar saloon with a synco 4 speed as they are not quiet.  Like you I built my car from a wreck, I had the gearbox checked out and modified to close ratio, when I first drove it I could not believe how noisy the gearbox was.  I removed it and had it checked out, nothing (much) was found.  It turned out to be a huge amount of end float on the camshaft, once I fixed that most of the noise went away but the gearbox is still noisy. Problem is all the noise combines and it's very hard to track down, as you are finding...I find earplugs most helpful.