well, i experimented with the different oils and viscositys not because of noise problems, but because of heat issues due to decreased volume because of my dual tcase project.

I plugged up a guage to measure the temp of the oil in the MUA tcase bath (the case that was cut in half, also the one that contains the Teras). basically, after about an hour of steady driving at 65mph, the guage will climb to its maximum reading of 250 degrees (and probably continue to get hotter).

I experimented with running 5w-30 full synthetic as well as full synthetic 80w-90 gear oil and about everything in between (as well as some additives). Basically, none of it made a difference, after 1hr of driving, the temp would still continue to climb out of control.

none of the oil choices i played with made much of a difference in sound, at least not that i picked up on (but again, thats not the problem i was trying to solve)

-Rob