transmission seal

i need to know if i need to take the tail end apart to change the seal. when i take the drive shaft out all i see is a black plastic ring which appears to look like the seal, is this infact the seal or is it in behind it? any info would be great

That black thing you're looking at is a felt "wiper" to protect the seal. That is easily removable, then you will see the seal. The seal is what is difficult to remove.