Transformers:Eclipse

is a New Role-Playing Game that take place Eons ago on Cybertron, the Great War is in its early stages, with the vicious Megatron
cutting a swath through the ranks of the Autobots. When the previous
Prime is killed, the High Council chooses a common data entry bot to
step up and become the new leader: Optimus Prime. But not everyone is
happy with the new choice, as his initial command decision is to
surrender Cybertron to the Decepticons. Meanwhile, Megatron works to
activate planetary scale engines which could remake the face of
Cybertron. He needs one thing to power them... and Optimus Prime has
it.
Eclipse was the first of any series to seriously
re-imagine G1 characters as they might have appeared on Cybertron.
Previously, pre-Earth Transformers were often just simplified versions
of their Earthen selves, if they were redesigned at all.

I'm guessing the Autobot Matrix? Either way it's a good plot.