Oscully pretty much sums it up. There is a cover over the engager to keep whatever fluid is inside from bubbling out and several enhancements to keep liquid from leaking....why?
I still don't know what fluid is supposed to work in the long term. I used 50-50 stop leak/gear lube- work Ok for a while, but slippage went up markedly and heat with slippage. I replaced that with auto transmission fluid which is designed to allow clutch lockup in its presence. Still had slippage and too much heat. Both quieted the transmission, but the slippage was too much to take. I replaced that with 7 or 8 ounces (an awful lot) of sticky, stringy "Green Grease" and the trans is acceptably quiet (no louder than with fluid), does not slip and get only a little warm (can easily rest your hand on it), not calf burning hot as it did with fluid.
If someone else knows of a better fluid, would love to hear it.