Wouldn't that affect the endplay of the input shaft? The bearing retainer serves several functions. Holds the front bearing in place,provides centering for the trans to bellhousing, sliding surface/guide for the throwout bearingand seals the trans input shaft.
I think that if that is were your leak is from that u didn't get the seal in streight? or damaged it when u pressed it in. Those seals will take up quite a bit of wear. also if the VENT is pluged u will develope pressure and cause a leak. Just more ideas.