46RH overdrive ratio.

Headintheclouds said

Let's ignore the lockup.

So 2400RPM. No overdrive. No lockup. Presumably some slippage.
Engage overdrive. Still no lockup. 1850RP. I assumed much the same slippage.
About 0.77:1

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I see what your getting at you think even with slippage it should maintain the same ratio, so slippage in your mind should be a fixed amount, no matter speed rpm power etc... Why would it be ? and obviously it's not.

Headintheclouds said

This suggests that either the gear ratio isn't 0.69:1 or that the slippage at 2400 is very different to that at 1850.

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