No, they couldn't. Kasem quit the Transformers cartoon in disgust back in the '80s after they did an episode in Season 3 with a Middle Eastern country called
Carbombya. Kasem, who is of Middle Eastern descent, demanded they change it, as it was clearly offensive, but the producers refused, so he walked. He also did the voice of the Autobots' computer Teletraan 1, which was destroyed in the multipart episode involving Carbombya. This is widely considered by the fanbase to be a direct result of Kasem quitting.
So yeah, it would probably be pretty damned hard to get Casey Kasem to do anything Transformers related again.