A further approach is always to hire a variable displacement pump.  When the pump is configured for very low displacement, it makes a low volume of oil circulation, leading to the hydraulic motor(s) to turn additional gradually. Like most automotive technological innovation, you will find pros and cons to CVT gearboxes https://beckettossqn.activosblog.com/33141249/an-unbiased-view-of-gearbox-cvt