My brother introduced me to using a vacuum pump to remove fluids. He was a boater and many boat engines must be drained that way. Advantage - one less place to potentially leak oil. While it does not easily remove the solids in a sump, in many cases it is easier and I have encountered several instances outside the marine field where that is the intended way to drain a fluid. This is what I use. https://www.ewktool.com/products/eb0280-6-5l-manual-oil-extractorNot too bad, maybe better get a suction pump for draining the primary. Access is easy at the inspection cap and you don´t have to change a seal. Could be used on some more places as well.
Vic
suction pump
syringe