Please help me understand I read the threads on this site about oil which just got me more confused. I have a 2008 Sportster 1200L I just bought. I am getting ready for it's first oil change. I have a service manual and it shows the main engine oil change which I am going to use 20/50w no problem. I get confused with the trans talk. MY question: Is the trans oil the same oil that is in the chain case or are they two different oils? I am changing the chain case oil with Spectro heavy duty primary chain oil. Am I missing changing the gear oil? Is there another drain plug I am missing? help I am so confuses!!!