Crossed beam experiments and quasiclassical trajectory computations on an ab initio potential energy surface are performed for the O(P-3) + CHD3(v=0) --> OH(V'=0) + CD3(v(2)=0,2) and OD(v'=0,1) + CHD2(v=0) reactions. Both experiment and theory show that the excitation functions display a concave-up behavior and the angular distributions are backward scattered, indicating a direct rebound mechanism and a tight-bend transition state. The reaction produces mainly ground-state products showing the dominance of a vibrationally adiabatic reaction pathway. The Standard histogram binning cannot reproduce the observed vibrational adiabaticity, Whereas Gausgian binning give good agreement with experitnent.