Abstract: A plunger type pump for use with heavy oil or oil mixed with sand is set forth. It incorporates bottom and top cylinders which are joined at a central bushing. A standing check valve in a polished tube enlargement at the top end cooperates with a bottom check valve in the bottom cylinder. A safety joint on the sucker rod string is included for easy connection. Another feature is a top end sleeve connected with a pin and J-slot arrangement held to a surrounding sleeve. Two sleeves are separated by breaking shear pins axial movement, rotation in a particular direction and additional axial movement to accomplish J-slot disengagement.