What is the recommended/manufacturer process for changing the oil?

Hi,

The preferred method is to extract it with a pump. They indicate this should be done when the engine is warm.

As far as special tooling, you need an engine vacuum pump. When the engine is at operating temperature, turn it off, remove the dipstick tube, and using the vacuum pump, extract the oil via the dipstick tube.

I attached information below that I feel you will find of interest.

Let me know if this helps.

Take care,

joe

See pics below.