During transmission reassembly, the check balls and thrust washers should be retained with a white petroleum jelly. Any other grease will most likely have a higher melting temperature than petroleum jelly and may cause coating and plugging of the oil filter screen, resulting in transmission failure.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.