GM-44626 is required to properly service the strut rod upper nut or oxygen sensor. GM-44626 is installed to the strut rod nut. A torque wrench is installed to GM-44626. A standard deep socket is then installed to retain the strut rod shaft. The torque wrench, in conjunction with GM-44626, are then used to properly tighten the strut rod nut. Attempts to service the strut rod nut without GM-44626 and approved methods may result in premature failure of the upper strut mount bearing.