Method of determining at least one shift parameter of a vehicle transmission

A method for determining at least one shift parameter of a vehicle transmission, the vehicle transmission comprising a first clutching device and a first speed ratio;

• a second clutching device and a second speed ratio;
• an input;
• and an output, wherein the input and the output of the vehicle transmission are connectable by engaging the first clutching device or the second clutching device, the method comprising:
• performing a shift by disengaging the first clutching device and/or engaging the second clutching device, wherein the first clutching device stops transferring torque through the vehicle transmission at a first time point, wherein the second clutching device starts transferring torque through the vehicle transmission at a second time point;
• determining the at least one shift parameter at the first time point and/or at the second time point;
• determining an amount of torque at the input of the vehicle transmission at the first time point and/or the second time point, wherein the at least one shift parameter is a first pressure-torque relationship determined at the first time point and/or a second pressure-torque relationship determined at the second time point, wherein the first pressure-torque relationship is stored in a first look up table and the second pressure-torque relationship is stored in a second look-up table, wherein the at least one shift parameter is a second friction coefficient μ2 of the second clutching device, wherein the second friction coefficient μ2 is based on the second pressure-torque relationship and geometry of the second clutching device and/or wherein the shift parameter is a first friction coefficient μ1 of the first clutching device, wherein the first friction coefficient μ1 is based on the first pressure-torque relationship and geometry of the first clutching device;
• and
• determining the first friction coefficient μ1 and/or the second friction coefficient μ2 and comparing the first friction coefficient μ1 and/or the second friction coefficient μ2 with a predetermined threshold.