I know many here including Doug won't agree at all with me. I have a 2000 with hyd. levelers. I bought it this last November, 2016. My Southwind 32v with a slide has 109,000 miles now, when I bought it it had 104,000. From 2010 till 2016 it had 400 miles so it sat a lot.
A front and rear jack leaked enough that I had to add fluid after using them because the low level switch (jacks down) kept the alarm going while driving.
I was facing the same problem as you, spending loads to fix a stupid oil leak. My solution and it seemed to stop all leaking, ALL, was a 1/2 a quart of Lucas atf stop leak. My reservoir leaked down and I added 1/2 a Quart to top it off. I worked the jacks up and down many times while on trips, those 2 jacks still leaked, but, within 2 months ALL leaking quit. The rams all looked new from the start, I kept them clean and sprayed down With silicone. I leave the jacks extended on my concrete pad I had laid for the RV. I even cleaned the Jack pads and repainted them black. Zero leakage now. I never had to add another drop to the reservoir (so far).
Now some will say, "the jacks and their line is a closed system, it has no flow so the stop leak in the reservoir will never get to the jack". Whatever, mine stopped leaking, I spent a few dollars and something fixed it. The more I use the jacks, the better they seem to work.