Yet another system is to hire a variable displacement pump.  In the event the pump is configured for minimal displacement, it makes a low quantity of oil flow, leading to the hydraulic motor(s) to turn more bit by bit. Like most automotive technologies, you'll find positives and negatives to CVT gearboxes https://garretthjnlk.tokka-blog.com/34432137/considerations-to-know-about-gearbox-cvt