Engine/clutch/gearbox/diff - about to go bang?

[ChrisE]

Hi there, hoping people can help me.

This is our Long Four, 1929 that has been in the family since 1975 although at one point Dad sold it so we bought it back!

Something is making a lot of banging noise and feels like it is about to go bang one final time. I then checked the gearbox and all the oil was missing. I have replenished that oil however it still feels as bad when running it with the rear axle up on stands.

Now I have just looked in the diff (as much as you can through an oil plug with a torch) and that’s totally dry. I’ve never, never looked in there before.

What do I do? Do I use the same oil that is in the gearbox? The oil plug is so low, it will only take, and I’m guessing half-a-teacup full before it drains back out of the hole.

Then take it to the road and see how it sounds?

Help! Chris (Austwick – Yorkshire Dales)

(ps I was massaging TipTop Engineering of Huddersfield last night who seemed very helpful)

gearbox video can be seen here https://photos.app.goo.gl/5N3jfLzuE27McYAU6

diff and gearbox photos https://photos.app.goo.gl/NdGTXBtMzxKUBpdc8

[Keith Clements]

Hi Chris,

I would suggest looking at the first aid list in Member Services to see if there is a club member close by. You should also have access to the JowettTalk library to look for relevant manuals.

You should also get some responses from pre-war owners here.

[Tony Fearn]

"Something is making a lot of banging noise"

Hi Chris,
Well, where do we start.
My Jowetts have never 'banged' so I'm at a bit of a loss as how to advise.
I'm surprised that after owning your '29 again for some time, you haven't routinely maintained it.
There are several booklets in the Technical Section of JowettTalk that are very useful, and as you are a JCC member, you'll be able to access them.

My first thoughts are:-
The engine itself, running the gears in the box, sounds to be a bit noisy from the video. But I stress that I am not an engineer.

Is the flywheel tight, or has the flywheel nut come loose?
Does the flywheel move significantly backwards and forwards when you pull and push it in line with the crankshaft.

Are the flexible discs at each end of the prop-shaft in good order?

I hope other pre-war chaps will add to these suggestions, but if you can't pin-point the area of 'banging', they might not be able to help.

I use Hypoid 90s in the rear axle, whether or not that is correct I don't know, but I've had one of my Jowetts since 1962, and I haven't had a problem with those gears.

In my early 30s Jowetts there is a cast-iron filler plug on top of the differential, and a lower similar plug at the rear of the aluminium ball.
The brass plug on the bottom is only for draining the differential.

I remove both filler screws and use the top one to fill the diff.. When the oil is just coming out of the lower one, there is enough oil in the diff..

If I remember correctly, when you lift up the rear seat squab, there's a removeable plate that lets you visualise the top of the rear axle.
There may be (or not) a top filler plug. If not then you'll have to use the lower one to fill the diff. and when it dribbles out, it's full.
The crown-wheel periphery is close to the bottom of the aluminium casing, and whilst rotating, dips into the oil thereby splashing it all around the inside.

Sometime ago I posted a few photos of the pre-war differential, so if you want to know what's in there, have a look, on this Pre-war section, at my post about 1930s half-shaft of June 27th 2021.

I hope you know where all the grease nipples are.

Best wishes,

Tony.

P.S. I'm in Clayton-le-Moors, and have been to Malham and Settle today with the family. After I returned home I read your post, Sod's law isn't it.
Give me a ring if you wish, I'm in the membership list, or come on over if you'd rather.

[Nick Webster]

That gearbox oil looks like it has water in it. Could have been in the container if already open or might have been condensation In the box. It needs flushing out.

Nick

[Tony Fearn]

Hi Chris.
Have you an update at the moment?
Tony.

[Brucegirvan]

Dear Chris
Apologies for taking sooooo long to respond. Picking up on a few points:
Gearbox - 90SAE
Rear Diff - 140SAE
Best to use someone like Millers or Castrol vintage. Modern oils are a a no no particularly for vintage engines, where I use 20/50.

Tony’s advice is great. If you overfill the diff the oil will start to fill the half shaft casings and can pass the felt seals at the end and get into the drums.

If your beautiful Jowett has not run for some years I’d check those felt seals - rear wheels off and the pull the drums and housings. JCS sell spare seals for not very many pennies and having had oil in a drum, all I can say is it really, really is best to avoid it!

From your gearbox video it looks like someone was injecting grease in - 90 oil is better as you need a lubricant that flows clear from the gear meshing carrying heat and any contamination with it. Here is where the right oil helps as you need the contaminants to sink and not stay suspended in the oil as modern oils will do where they are designed to circulate through a filter, which we vintage cars don’t have, so you want the oils to drop contaminants to the bottom. I think the gearbox sounded OK, the clunk was somewhere else but you said you had it on stands so we’re those noises from the front or rear?

And - I assume you had engine oil and good pressure? Oil the valve steam and followers and check the oil breather flap to make sure that has not perished or is missing. If it had not run for some time you can expect a few leaks and squeaks.

Can’t wait to see it running