In the G1 continuity, Unicron attacks the Earth and Cybertron in the year 2005, and during a battle with Megatron, Optimus dies.
Of course, Optimus is revived in later episodes of the tv show. The first time he is "revived" is in the episode Dark Awakening (S03E08). Hot Rod briefly discusses how long Optimus has been dead.
Hot Rod: Come on guys, he's just shook up a little. You'd be too, if you'd been dead for years.
It had always been my understanding that Season 3 of the G1 cartoon took place very soon after the movie. Daniel's age does not appear to change between the movie and the episodes of season 3.
How many years had Optimus been dead by this point? Alternatively, how many years took place between the end of Transformers: The Movie and Season 3 of the TV show?