Help needed with flickering speedo / clock

Hi

I have a dodgy speedo on my Mk 1  1.8litre Clipper.
I have heard that it is a common fault and I read somewhere that it is related to the speedo cable or the 'drive gear' of the cable.
I have seen on ebay there are 2 types of 'drive gear'

A red 15 tooth drive gear, seen here:
red cog

And
A clear 16 tooth drive gear seen here.
clear cog

Does anyone know which drive gear I would need?
Would I also need a new speedo unit completely?

Any help very much appreciated.

Thanks

need to tell us the gearbox code you have chap, then we can advise
its on the flat plate on the bottom of the bellhousing, 2 or 3 digit code followed by 6 numbers

Thanks for that.
I have a photo of what is potentially the code but im not sure that it is. Its a flat blue plate

There is a picture here:  2 pictures
Sorry I couldnt figure out how you put the photos directly on the forum.

I think this blue plate is on the brake servo though. Perhaps if you can tell me in relation to the photograph, where abouts this number is written. I am living abroad currently so I will be relating the info to someone else. From memory there was a number engraved into the metal work, would this be it?

can it be seen from looking in the engine bay, or it is on the underside of the car?

no thats the brake servo
the box code is underneath  the gearbox, i.e. you have to lie down and look

2nd pic, on the square yellow box:
020 Oil

Ah great pic, i see where you mean now.

I will ask someone to check it for me and let you know in due course

Hi,

OK so I have checked and the code under the gearbox is

AUG28042.

Underneath the letter G there is a 7, so potentially the code is AUG 7 28042

Please could you help identify what I need to do next?

Thanks

ok, for that box you need a red speedo gear. btw, its a late mk2 8v GTI box you have there

Great, thanks for the reply.

Would this mean that this is not the original gear box, ie. it has been replaced with one from the mk 2 gti,

or it just happens to be the same as the one in the mk 2 gti.

Ive seen the cogs/speedo gear thing for sale on ebay so i will buy the red one.
Is there only 1 type of speedo cable ( I have a bright white one) or do i need to buy a new one of these as well?

Thanks

if its a very late clipper with injection then thats the right box, they used gti boxes on those. if its a carby the box has been replaced, but its a good one to have sporty ratios

the cables are the same, just make sure the little circlip is there on the end otherwise you'll loose your nice new gear inside the box!