I design the model in FreeCAD. It was tried pumping water but oil should work too. The pump needs to be primed.

Material used Gaskets are printed in TPU Gears are printed in PETG Casing and Lid printed in PLA

You need 4x 608 Ball bearings (d=8mm D=22mm width=7mm) 16 Threaded insert M3 16 M3x12mm 2x 8mm Shaft min. length 60mm some sort of lubricant (Silicon Spray, grease)