Why does my CAT 966C keep tripping the 40-amp breaker when I try to start it after replacing the starter?

[Robert M.]

I'm having a starting issue with my CAT 966C. The starter stayed engaged while the machine was running, so I replaced it. Now, every time I try to start the loader, it trips the 40-amp breaker.

I've checked some wiring and connections but haven't found the problem yet. Has anyone dealt with this before or have any ideas on what to check next?