pump oil

Changing Jet Pump Oil There is an existing howto for this, but it has some unnecessary steps/missing some details, and maybe people don't want to download attachments (or are trying to view on their phone or whatever) so I thought I would write a new one while I was at it with a little better...

my 1989 sp runs super. but last fall I replaced the wear ring and impeller. when i started it on the trailer after the repairs the impeller scraped a bit at first but then it smoothed out quickly. then all of the gear oil dumped out the back! yikes...what did I do... or not do?