GM-52322 features an angled half-circle edge that surrounds the seal, ensuring 180° of contact with the seal and wedging under the seal's metal lip. Tapping the tool with a hammer forces the tool edge under the metal lip, raising the seal so it can then be pried out by tilting and using the L-shape bend in the tool as a lever fulcrum.
The tool has the added benefit of being able to be used for seal removal on-vehicle with the manual shaft in the transmission.