With 2007er Town Car without hesitation longer drive 160 km/h?

I’ve been the proud owner of a 2007 Lincoln Town Car for two weeks. I knew that the car “only” reached a top speed of 180 km/h – and since I don’t drive SOOO a lot of BAB, I can live with it. But I thought that you can actually drive this speed without hesitation. OK, it’s like that it gets tough above 160 anyway, but 160 would be desirable. Now I was warned: the gearbox would be too hot if you were to drive more than 160 km/h or Is that really so? Is there any remedy?