The aim of the study the resistance to friction in the lead screw-nut contact zone in a car scissor lift during its operation. In both cases of lack of lubricant and lubricated contact zone the stick-slip phenomena occurred therein. The analytical model of lead screw-nut assembly driven by electric motor was elaborated. During operation of such an assembly, lubricated stick-slip oscillations occurred with magnitudes smaller compared to the case of dry friction in the contact zone. During lifting the vehicle the friction torque values in the lead screw-nut contact zone lowered due to lowered contact pressure caused by lowered value of the force loading the contact zone due to changing values of angle between the lead screw and the lift arm. Contrary, during lowering the vehicles, the friction torque values in the lead screw-nut contact zone slightly increased. In case of PTFE-based lubricant, the values of the friction torque were over twice as low compared to the case of dry/boundary friction conditions in the analyzed contact zone. The use of lithium grease further lowered twice the friction torque values compared to the case of the PTFE-based lubricant.