Rear main seal 2002 Blazer - I did search first.
 

My buddy is looking to buy a 92 Blazer and the main seal is leaking. I know, I know, but he is dead set on it and wants to fix the leak. I am new here, but not new to much of this. Is there a sticky or does anyone know of a tech write up on the V6 rear main seal? He also says there is a half-moon shaped hole about 1/4" to 1/2 " in the bottom of the bell housing WTF? Sorry for being so wordy. Thanks in advance!!

You have to drop the transmission to get to the rear main seal. Get a Haynes or Chilton repair manual. The hole in the bell housing is probably an inspection hole for the drive plate that allows you to see if there is oil leaking from the seal.