[Arran]

I can confirm that Chrysler did offer a transistor car radio in 1956, but it was an extra cost option even with the Imperials, most of them got the tube models. I'm not sure who built them for Chrysler though, most of their sets prior to the 1957 cars were either Philco or Motorola built, the 1956 cars had a 12 volt electrical system, the 1955 cars did not. There was really no impetus to push transistor car radios at the time, transistors were quite expensive until 1959-60 or so, and portability, and current consumption were not really a concern, so it was more a marketing gimmick. By then field coil speakers, which were a big current hog in car radios, were a thing of the past in house sets as well. I think that Chrysler and Ford largely followed the same path, 12 volt vibrator radios came first, and then hybrid tube/transistor radios until 1963-64, by that time transistors were neither expensive, nor considered a technical marvel in a radio.
Regards
Arran