Transmission shaft: oil seal near the flexible joint (See photo)

Hello everyone,
while replacing the transmission shaft elastic joint I broke a small hard plastic gasket with a diameter of about 3 centimeters with a spring all around it: it looks like an oil seal that goes inside the transmission shaft not far from the joint elastic…
I couldn’t find the part anywhere, not even in the Jaguar manual…
Has anyone replaced this part?
A thousand thanks… :wink: