Lost reverse, need help finding it. 727

Trailbeast have you installed one of the super servos?
I can't seem to get the seal to slide past the retaining ring groove. Without the seal it slides right in.
I don't see how its even going to slide in with the stabilizing ring on it.
Any suggestions?
First I tried living it with transmission fluid, then I tried petolum jelly, as stated in one of the rebuild videos.

Put a hose clamp around the seal and tighten up pretty good, then stick it in the freezer for 20 min or so.
Be ready to put in in AS SOON as it comes out of the freezer.