Quote Originally Posted by kup View Post
It could be possible that there is a fair amount of time from the end of the Beast Wars to before the Maximals and Megatron arrives back on Cybertron, particularly when they are using a modified 4 million year old shuttle.
The Predecons had some knowledge. They could be from after the Transwarp wave made it to them. Ravage could have also sent some kind of information back, although that's a maybe.
Magmatron may have also studied various time periods so he could see the best point to insert his team in.