Product Service Bulletin 7-209 dated December 13, 1983 describes the use of a new solid pin used to properly orientate the pressure regulator bushing in the transmission case. This pin may fall out during transmission case cover and gasket removal.
The Figure below shows the location of the pressure regulator bushing pin in the case.
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.