I want to investigate how the contact stresses in the teeth of two helical gears are changed by time. The gears are shown below. The lower shaft is rotating at 6000 rpm and a moment (4000 N.m) is applied to another shaft. Contact and target surfaces are also defined, however, the results are very weird, not only there is not any contact between the gears, the larger gear is massively expanded! I have sent some pictures that show the details of the modeling. I will appreciate if you help me to solve this problem.