[rs72z]

If you can get to some air you can check it by putting air to the hole in the inner bore of the drum and see if the piston moves the clutches all the way out.

The inside lip of the drum where the seals start down in the drum will cut the seals going in if you force it at all. Using a feeler gauge you go around the outside of the piston then the inside bore of the piston to get the seals to start down past the lip on the bore.

The only piston you can force in is the low/reverse in the bottom of the case because they use square cut seals not lip seals.
If you need to see how it's done i will try and take a video this weekend and upload it.