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Similarly, the role of Tenshinhan, whose voice actor (Hirotaka Suzuoki) died in the intervening years between Z and Kai, and was replaced in Kai by Hikaru Midorikawa.
Likewise with Dende's voice actress (Tomiko Suzuki), who passed away in 2003; she was replaced by Aya Hirano.
Takeshi Aono, Kami-Sama's Japanese voice actor, suffered a stroke in between the Freiza and Cell sagas, so Bin Shimada took over for his final few appearances. Aono subsequently passed away in 2012.
Channel Hop: The show was initially licensed by Nickelodeon and aired on Nick Toons with edits for content. After the show was taken off the air due to Nickelodeon presumably losing the license, Kai moved to [adult swim] and currently airs uncut on the revived Toonami.
A minor example for the show's run on broadcast networks. 4Kids Entertainment licensed the show for airing on Toonzai. When Toonzai ended and was replaced by the Saban Brands-run Vortexx, Kai remained as one of the holdovers from Toonzai (and was notably one of the few shows that continued to air on Vortexx until that block was replaced).
Another nod in one episode Vegeta shoots one of Freiza's men and the Wilhelm Scream is used, in Dragonball Z Abridged the scream was used in the same scene right after two of Freiza's henchmen were discussing it.
Hey, It's That Voice!: Those who watch Funimation's One Piece dub will easily recognize Gohan, Piccolo, and Krillin as Luffy, Zoro, and Usopp, respectively. In fact, a lot of the new voices are from the One Piece dub (Freeza=Johnny, Dodoria=Crocodile, Bulma=Tashigi, and so on). Considering both were dubbed by Funimation's in-house voice cast, that's no surprise.
Keep Circulating the Tapes: 95 episodes of Dragon Ball Kai with the Kenji Yamamoto score aired from April 5, 2009 to March 6, 2011, before he was fired by Toei Company for plagiarism, mainly the scores for Avatar and Terminator: Salvation. Reruns of these particular episodes have since replaced it with the Shunsuke Kikuchi score from the Z series. On the respective Japanese Blu-Ray, DVD, and American DVD/Blu-Rays, the Yamamoto score was intact on episodes #001-#076, #001-#072, and #001-#052. So your best bet to getting ALL 95 Kai episodes with the Yamamoto score would be to trade with someone who recorded the show off of Fuji Television during the above-mentioned period in the run.
The Other Darrin: Used for quite a few characters whose original voice actors were either dead or unavailable. Several characters were replaced in the dub as well like Gohan and Bulma (the narrator was also replaced), among others.
Also replacing Joji Yanami as Babidi in the Buu arc. (Despite Yanami still being on the show as Kaio and the Narrator.)
Yuko Minaguchi is being replaced by Shino Kakinuma as Videl, due to Minaguchi living abroad now.
Todd Haberkorn, the voice of Allen Walker in D.Gray-Man, took over duties as Android 19, sounding even more robotic than the original dub voice. Similarly, Colleen Clinkenbeard now voices Android 18. Although her original voice actress, Meredith McCoy, was supposedly contacted, Clinkenbeard was brought in anyway as a last minute substitute (since she had filled in for a video game before, and was voicing Gohan anyway).
The broadcast dub also switched Sean Schemmel for Vic Mignogna as the singer for the shortened opening, while the second DVD boxset switched him for Justin Cook.
The Mexican Spanish dub is heavily criticized for not bringing back half the cast, including the voices for Goku, Gohan, Vegeta, and Frieza. This was apparently because of the smaller budget, and the original voice actors asking for more money. However, Laura Torres (the original Spanish voice of Gohan) was brought back to voice Kid Goku in a few flashbacks.
The Mexican Spanish dub has another interesting case: Yajirobe is voiced by the daughter of the original Mexican voice actress, since her mother died in a house accident years ago between the original DBZ and Kai.