Transformers: Cybertron

Forst off, ignore the other user comment, this show was never on prime time in japan. it airs at around 8 in the morning. Also, the Transformers have always had accents (going all the way back to perceptor in G1), even in the Japanese version of the shows. of course, in japan they have various Japanese accents, and since those accents are impossible to carry over into English, they are substituted by various English accents.

Cybertron is a very faithful dub of Galaxy Force, with very few changes aside from names of characters and a few objects, and having Override as a female, where in japan the character (named Nitro Convoy) is a male. of course, this is nothing Hasbro did, the character was supposed to be female from the start. Takara is the one that changed it.

If you can't watch the Japanese original, Transformers Cybertron is the best TF series since beast wars. all you'll be missing out on is the vocal Japanese songs.