Posted April 21, 200816 yr comment_244781 Ok So I swapped a 1979 280zx 5 spd in the 71 240z. How do I get the speedometer to be accurate since the gear ratios are different now? Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/ Share on other sites More sharing options...
April 21, 200816 yr comment_244782 Change out the rear end to the same gears as the 280ZX?? I really don't know, but its a guess. Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/#findComment-244782 Share on other sites More sharing options...
April 21, 200816 yr comment_244784 Check out this website and scroll down to where it says How to keep the speedometer correct and talks about the various speedo cogs. http://datsunzgarage.com/engine/ Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/#findComment-244784 Share on other sites More sharing options...
April 21, 200816 yr comment_244785 Take it to a shop and let them calibrate it. Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/#findComment-244785 Share on other sites More sharing options...
April 21, 200816 yr comment_244791 The speedo gear is matched to the rear-end gearing. So just use the speedo gear out of your stock 4spd. You may have to swap the speedo gear carrier... using the gear itself from your original 4spd., but put in the ZX speedo gear carrier. As I recall there is a "pin" that holds the speedo gear in the speedo gear carrier. (the carrier bolts into the transmission - and speedo gear is inside the carrier).If you have changed the rear gear ratio - then you need a speedo gear to match it.FWIW,Carl B. Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/#findComment-244791 Share on other sites More sharing options...
April 21, 200816 yr Author comment_244830 Sounds good thanks Carl! Link to comment https://www.classiczcars.com/forums/topic/27793-tranny-swap-how-to-get-the-speedo-correct/#findComment-244830 Share on other sites More sharing options...
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