Gearbox change wrong speed

[Bezerra]

Hi guys,
Recently change my mk2 gearbox (4speeds) to a 4 speeds with overdrive.

Everything works fine but it shows wrong speed on the odometer.

Does anyone know what’s wrong?

[metalworker0]

Think you are going to be changing this out

https://www.motomobil.com/en/products/g ... 149020-4-h

As you can see there are four different ones with different amount of teeth

The amount of teeth dictates ...what final ratio you have in the drive to the speedo

Which one / what that is? ...well you are going to have to do some more research.

Each different combination of gearbox and rear diff, requires a different speedo drive gear

To help you along

putting this into google

6014902 ford

Brings up the ford "zap parts site" in google. it brings page with with the gearbox parts list, one of the results has the over drive gearbox ..on the parts diagrams underneath. are the different ratios for the gearbox / diff combination..unfortunately it's in a foreign language and the google translate does not work on it ...and i cant get at this information from the english version .

all the best.mark

[dumper]

Back in the day I fitted a few o/d boxes and changed dash to cortina one with clock in it used to do it by trial and error as the drive gears were available in breakers yards must have been the same gear type as in the 4 speed have you tried the drive out of your old box they are colour-coded so if they are different colours and still don’t work at least you’ll eliminate two from the list of available ones.