Yo SeaDooYa:
Seems like the Thread gotten off track from the original question.
Reading your post, you recommended using a 75-90 synthetic!
On that note, when I went to Auto Zone to fetch some Jet Pump (JP) Oil, I recall reading previously on the Forum that a good substitute and much cheaper in price was to fetch synthetic Gear Oil, 75-90, just like you recommended.
However, when I read the label, 75-90 Gear Oil is a blend and 75-140 is full synthetic.
Can I use the latter "Gear Oil" (75-140) since it is full synthetic, or, search for the 75-90?
FYI, Wal-Marts brand Tech Gear Lub is 1/2 that of the major brand and is manufactured by either Penzoil or Quaker. The same for its brand of oil.