Difficulties Encountered in the Correlation of Vehicle Response to Bench Testing of Driveline Gearboxes for NVH Attributes

Correlating a bench test stand to predict the response of a driveline gearbox in the vehicle can be very difficult. Many sources of variation and error may prevent correlation. This paper outlines the issues related to both vehicle and bench testing that prevents proper correlation. The importance of understanding both the NVH measurements and statistics are vital to proper interpretation. The identified issues are backed up with real test cases where these issues occurred in a series production gearbox program. A successful correlation case study is presented for comparison.