T-56 Magnum Speedo Gear
 

T-56 Magnum with Yellow, 7-tooth Drive Gear. Car has 26” rear tire and 3.70 Rear Gear. Every online calculator tells me I need the Red 21 tooth driven gear. Got that installed and factory speedo is reading 10 mph fast.

I’m happy to try the White 23 tooth driven gear, but keep running into forums where folks have posted that the 23 tooth gear has durability issues and gets chewed up. Apparently, in order to fit 23 teeth on the driven gear and keep it the right size to fit in the trans end cable fitting, the teeth end up being very fine.

One source online suggests that the problem is running the 23 tooth Driven Gear with the 6-tooth Drive gear that was common in the T-5 transmission. The size discrepancy between the teeth on those gears is what (that source) says causes the 23 tooth Driven Gear to take a beating. Those folks end up pulling the trans to replace the 6 tooth Drive gear with the 7 tooth Drive Gear to get them into a range where the stronger 18-21 tooth Driven Gears can be used.

I’m wondering if anyone has run the White 23 tooth Driven Gear with the Yellow 7-tooth Drive Gear in the T-56 Magnum (or TKO 600) and if the 23 tooth Driven Gear held up in that application?

Thank you!