The article discusses a mechanical stepless transmission capable of self-control in a wide range of gear ratios depending on the traction load of the vehicle. Mechanical stepless transmission is based on using angular oscillations of freewheel mechanisms (FWM) and elastic linkages (torsion shafts) enabling multiflow transformation of mechanical power, ensuring the automatic increase of torque on the output shaft of the transmission with a reduction in its frequency or smooth increase of its frequency with concurrent reduction of torque. The article gives basic mathematical dependencies and makes computer simulation of transmission operation. The article shows a Simulink design model that includes an engine block to create an incoming flow of torque and power, a transmission block with parallel branches of freewheels modules for smoothing and converting torque, and a block for determining torque, power, and efficiency at the output of the transmission. The graphs show that the use of parallel freewheel mechanisms allows us to smooth the flow of output torque and power, and greatly reduces the inertial performance of the transmission at the starting moment. The results of the calculations and their analysis show that the proposed self-controlled mechanical stepless transmission has a high torque ratio and ensures the continuous transfer of power to the output shaft with high efficiency. The obtained characteristics tell us that the proposed transmission has an advantage over mechanical transmissions because of the quick response at the moment of vehicle start and the ability to continuously deliver power and torque flow to the output shaft or drive wheels.