I'm working on a 2004 Cat MBN C15. The jake brake has always given the driver trouble. After closer inspection of the assemblies, I found one of them cracked. It has the Pac Brake brand on it. For some odd reason I was told that only the MBN engines used this particular jake brake assembly. I was told, as with any C15, you can change out all of the jake brake assemblies, if you can't find that particular one. It's been like pulling teeth trying to find a good used one. Which model or particular year jake brakes are you partial to? Is there a particular set that works better than the others? Thanks in advance!