The oil filler on my truck was leaking when I got it. There was a bunch of goop on it that must have sealed it for awhile. I took it apart today to try to fix it right and the threads on the extension piece were all broken off. The piece that screws in the timing cover as well as the filler cap itself are fine. Can I get that piece from mopar, or cummins?

 

You can get it from Cummins.

 

Can you unscrew the extension and screw the cap onto the piece that threads into the timing case?