I guess I'm still not seeing this correctly, but it appears to me that this is intended to be re-assembled through the bottom plate opening. No machining necessary.
YANMAR YM336D/W Loader JOHN DEERE 850/ W Loader 2WD&4WD Kubota RTV 900
I think you would want the opening to be as close as possible to avoid allowing dirt and grit from entering and destroying the seal prematurely. If my freind at the machine shop had not assured me he could do the job your idea was going to be my next step.
YANMAR YM336D/W Loader JOHN DEERE 850/ W Loader 2WD&4WD Kubota RTV 900
Got the housings back today.Got it put back together right as it got dark so I thought I would let it sit over night before I finish filling it with 90w. I took some pictures. One is of the housing showing the boring job.One is showing the housing with the sleeve inserted showing how it fits and the other is the housing with the seal installed.Everything seemed to go together good. I'll check it out better tomorrow.
I hope that solves the problem.... When I replaced my seals. It took a couple months of operating B-4 they started weeping again.... I hope this fixes yours.....Mine isn't really that bad
YANMAR YM336D/W Loader JOHN DEERE 850/ W Loader 2WD&4WD Kubota RTV 900
I haven't had time to work the tractor yet but did run it around for about an hour and everythink seems fine. No leaks so far.Going to mow some pasture this weekend. If it ever has the problem again it will be an easy repair the next time.