Re: pics of plugged oil passge between lower and upper housings
I went to Lowes and picked up a small tapered rubber plug. Fit nicely half-way (make sure it is tapered and will not fit all the way into the hole! you might lose it!). Held 15 PSIG just fine.
Before this, I simply cleaned the area around the port with alcohol and used a piec of clear packaging tape. Again, held 15 PSIG and 7 inches Hg just fine.
Note that you cannot test the upper half of a gen two drive without somehow plugging the hole where the vertical shaft goes (if you really want to do this, then use a dummy shaft the same diameter as the vertical shaft to get a seal in the two seals in the upper housing. I am not sure I have read anywhere on here where anyone has done this independent test of a GenII upper.
I would just reassemble the drive and do the pressure test, using soapy water solution to spray on those seals via the exhaust port of the drive. (do this with the drive upside down so the soapy water stays on the seals and gives you good indication)