i need to know the name of the tool used to install a rear main seal... anyone have any ideas?? im doing this job this weekend

 

Are you asking about the two-piece rear main or one-piece? A one-piece can be pressed in place with a seal driver. A two-piece can usually be pulled in place with a packing tool. Usually, packing tools are sold in sets, and can be found at any industrial pump supplier and better plumbing supply houses.