I've done this on an L120 by increasing the engine speed from 3000 to 3500. So the K46 tranny input went up to 3500 as well.
they hydro tranny is actually quite simple to understand as far as ratios. The tranny has a pump and motor, and then some gears. The gears have a ratio. And the pump-motor have a cc-cc per revolution ratio as well.
For the K46, the pump and motor are 7 and 10cc respectively. So for every revolution of the pump, the motor makes 0.7 revolution. Now if you increase speed on the pump (input shaft), you will increase speed on the motor.
Of course, there would be some increased wear & tear on the system, but it can be done, and it's not going to kill the tranny overnight.... I ran my L120 set-up that way for over 2 years with no problem. But that's no guarantee.
