Well, it's a moot point now, it sold this morning. The seller said it leaked oil on his driveway and in looking at the 1840 manual and how those tandem pumps are bolted together, I thought that there might be an easy fix. Obviously, so did someone else. I have had my 1840 since 1997 when I bought it new. Over the years people have watched me do a tremendous amount of work with it so much so that now they want their own units. One being my daughter. She asked me to find her one just like mine so that she could use all my attachments, right after I found a smoking deal on one for a friend of mine. Sure is hard to find specimens in relatively good condition. Thanks for your help though. It's back to craigslist, ebay and ritchie bros. Tom
Don't be too hard on yourself, i don't believe it would have been an easy fix.
I have only had this issue once that turned out to be an easy fix, the others were pump wear.
An oil leak could allow air to get in the system, you would get noise and possible power loss at all times, not just when hot.
As for test ports, there will not be a dedicated port. You have 3 pumps in a hydrostatic system, to test it properly you need to tap into all the lines to measure pressure/and flow at operating temperature.
If your machine has a universal attachment plate, you don't need to look at a case, you have many options to get a good deal on.
Good luck with the search.