Just doing some more research on this. Threebond 1215 is not an easy find at small retail quantities.
Also found interesting info on aerobic vs. anaerobic curing.
Last, found this Subaru tech article...
Note very limited recommendation for use of "fujibond"
It looks like the 3M T-3 Silicone (black) #08670 is the duct tape of sealants with Loctite/Permatex #599 Ultra-gray a close second. Except, the 3M appears to be more impossible to find than the Threebond
Look at the first row... "Bearing Cap #5", Is that the rear main seal? I don't think you silicone the main bearing down, do you? I know it is the thrust bearing, but that would be very weird.