Upon arrival on prehistoric Earth, Dinobot was disappointed with Megatron not destroying the Maximals when they had the chance, and that they did not appear to be on Earth, so he challenged him to a battle for leadership of the Predacons. However, Scorponok sent him flying into the distance with a missile.
Dinobot then challenged Optimus Primal to a battle for leadership of the Maximals, changing his activation code to "Dinobot Maximize". Their fight was interrupted by attacks from the Predacons, during which Optimus saved Dinobot from falling to his death. The Predacons' attacks revealed a mountain full of Energon where the Maximals (including Dinobot) and the Predacons fought in beast form. When Megatron transformed (endangering his life, as those unstable energon crystals could destroy them as robots in less than a minute) and shot a missile at Optimus, who was injured in the battle, Dinobot deflected the missile away from him.
From here, Dinobot remained on the Maximals' side (though he nearly rejoined the Predacons at one point). He never became a Transmetal like many of the others did in Season 2. In the episode "Code of Hero", Dinobot received many injuries from the Predacons when he was defending the protohumans from them. He destroyed the Golden Disk, but died from his injuries and loss of energy.
In Season 3, Dinobot was later cloned by Megatron, not for the first time, as in Season 1, in the episode "Double Dinobot", Megatron made a clone of Dinobot that could not transform. In the end, this clone was eaten by Dinobot. Dinobot II, the second clone, and a Transmetal, was on the Predacons' side for most of Season 3 until the death of Rampage, and was killed helping the Maximals escape.