Speedometer gear change?

Got a 65 Newport and I need to change the speedometer gear in the tranny due to larger tires. Will a standard speedometer gear work or is there something special about a 65? I've checked ebay and most of the ads state for use in 66 and up transmissions.

Not sure if '65 has changed over to the larger gears or not. The earlier ones have fewer teeth selections avail & might need to use one of those adapter gismo's that let you change the ratios w it.

I know for sure the 4 speeds have the old gear style.Pretty sure the autos do also.The gears arent as avaliabe as the new style.I was looking for one for my 65 B body.The 3.23 one dosent work real well when I have the 4.88s in it.With the 3.91s I know the speedo is off about 20 percent fast.Rocky

I've been looking for a speedo gear for my old pushbutton trans for years. Imperial services at one time was talking about repopping those but haven't to my knowledge. I ended up buying a GPS heads up speedometer (displays the speed on the windshield) from Amazon.com called a HG100 from GlobalTop Technology. It was $65 but I see they're no longer available. It was much cheaper than the gear adapter plus you can you it in any vehicle and you don't have to worry about recal with gears changes.

Jim

Thanks for the responses. I guess I'll just use my GPS as a to figure out how much I'm off.

Look on the side w the speedo cable and the early one has a smaller hole/assy and a flat plate that bolts it in as opposed to the '66 up one w the larger alum speedo adapter w the horseshoe clamp. That'd b a good start figuring how much error you have & if you do source the correct gear which'll make the odo correct (do measure ACTUAL tire dia w a piece of flat stock on top of the tire & measuring rollout is even better) & interstate mile markers are perfect for checking it (odo). most of the time the speedo will then also come in correct (check w digital road side speed signs)but the speedo is a sort of seperate function & if not correct the speedo head will need to go to a speedometer specialty shop to recalibrate but as you know the pinion has to have the correct teeth count 1st.

The '65 and earlier transmissions use the smaller pinion with a range of only 16-21 teeth.

When using a calculator, the early drive gear has 8 teeth instead of the 13 teeth on the '66 and later.

John is that tooth count the same for 904's?

The '65 and earlier transmissions use the smaller pinion with a range of only 16-21 teeth.

When using a calculator, the early drive gear has 8 teeth instead of the 13 teeth on the '66 and later.


So if I do the math, the 32 tooth gear I needed would come out to 19.7 or 20 on the earlier gear drive. Now where do I get this small 20 tooth gear?

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Now where do I get this small 20 tooth gear?

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(as you know) Moparts "trans parts wanted"/eGay/one of the early trans specialists, Imperial? Ask "Joesixpack" on here, if it's NOS & out there he has it (for sale)