Go to the Jacobs or Cummins website and read all about it. You can even download the installation and operation instructions. It should answer all your questions.
Tomeygun said:2006 you can, works awesome too!
What is different on them that they will not fit a 305/555 on an 04?
TowPro said:If you don't like that big old knob to turn it on and off, Gino's has a replacment shift knob with the switch built in.
nickleinonen said:the brake casting is different, as it has a 4" outlet instead of the 3. 5" outlet the 555 has. i know that, but as for other changes, i don't know??