To be fair the guy says there from a late 90's blaster converted to a hydraulic brake set up.
So he isnt claiming they are 03+ spindles gsustaitav19822 posted that they are 03+ spindles.
None the less I'm gonna bid on them.
So I did a leak down test that went great but while running I noticed the trans vent had vacuum so I tested it with a little oil and it sucked right up,
that doesn't seem normal to me.
There should be no reason to block that. you can do what blaaster said and put that into a cup of water and then do a leak down test and if you get bubbles your crank seal is leaking. If you do that and no bubbles you need to split the case.
Unless you have your trans breather whole plugged I don't see how a leaky collar is gonna push through the case halves.
IMO you need to split the case.