Okay. Your E4OD transmission throws an occasional fit and the OD light starts flashing. This is not a good thing. You're concerned or you wouldn't be posting about it. In my opinion, the transmission has a problem, and it will only get worse. These things seldom cure themselves. It may be that it needs a simple FIPL adjustment. That would be the best possibility. Or it could be that this is the first indication that the transmission needs rebuilding.
It's been suggested that you pull the transmission codes with a scanner. That's the first step in determining what is wrong. These codes are stored. They do not go away just because the transmission decides to act nice again. The codes are still there, waiting for you to pull them. So, pull the codes, and report back to us. Do not disconnect the batteries. That would delete the codes.
Scan for those codes and report back.