Borg Warner missing parts?

Hi All
I've had a workshop accident......
On starting to dismantle the front and rear clutch assembly, I held on to the rear clutch outer drum, and turned the assembly vertical. Straight away the forward sun gear and shaft fell right out to the floor. About a second later, I heard another part fall, bounce and strike something nearby on the garage floor, but despite a thorough search, I can't see any part on the floor. I reassembled the shaft into the rear clutch and through into the front clutch, everything looks as it did before, but I'm paranoid about having missed something. Given that neither clutch was dismantled, and I still have the thrust bearings (needle, plain steel and bronze), could there be another small part I am missing? I have checked my Borg Warner manual, don't think there is anything missing by looking at the diagrams, but I am worried I have missed something.
Thanks in advance, again, for any help! IMG_20200521_165408.jpg
IMG_20200521_155421.jpg IMG_20200521_155133.jpg
Just check the front of the Sun shaft, when it hit the floor it might have dislodged the relief ball valve in the middle of the shaft itself ( worth checking its free moving anyway ) I doubt it came out but good to check it.
I hadn't thought of that, thanks for the idea, I will check that.
checked - ball still in place, functions fine.
Rear clutch friction plates totally worn out, all down to bare steel, front clutch friction plates are like new, even down to the manufacturer's markings.
Thanks again for the help, I think I heard something else falling to the floor, probably a screwdriver.