240z speedo pinion

[Graham Palmer]

Hi all, my 73 240z reads probably 15% over on the speedo vs GPS, I dont know the diff ratio, or the pinion ratio/colour. I have also changed from stock slot mags to Rotas. Any tips on the easiest route to determine which speedo pinion I should change to?..

Or, do I have to take the diff cover off?...guess there is a gasket on there ?..

Thanks

 

[Mr Tenno]

Isn't this pretty much standard on all cars?

 

[jonbills]

yep

 

[alienpoker]

Not much to do with the diff -unless you changed it. It’s because you changed your wheel size from stock, so it reads wrong. There’s a pinion on the side of the tranny. Just follow the speedo cable & you’ll find it. Theres a ‘keeper’ with a bolt and then it pulls out, It’s straightforward. Search other forums on how to determine the number of teeth you need on the pinion gear.