ZF集团在1973年末就为开发和销售一种用于市区客车的全自动变速器作好了充分准备。那时即已清楚,尽管原有的半自动3HM40和60型,以及全自动的双速2HD45型有着已被证明的记录,但并不能满足未来的产品要求。在决策进行技术开发之前,作了市场研究,已活跃于该市场的未来竞争者产品的技术分析,客车的总 In late 1973, the ZF Group was fully prepared to develop and market a fully automatic transmission for city buses. At that time, it was clear that although the original semi-automatic 3HM40 and 60 models, as well as the fully automatic 2-speed 2HD45 model, had proven track records, they did not meet future product requirements. Before making a decision on technology development, a market research study was conducted on the technical analysis of future competitor products active in that market,