1984 2.8 chevy s-10 motor jasper, help?

[mj W]

i 've been driving for 9 years, this is the first time my oil gauge needle is bouncing around. the motor still sounds ok. i'm looking for the oil sending unit or where is the oil pump please? i've never had to replace these parts; thank you, mary

 

[joystoy33]

Shouldn't be too far from the oil filter.