Cat 345C swing gear

I have major play in my cat 345C swing gear I believe its called. The play is between my upper structure and undercarriage frame that the machine swings on. Can anyone give me advice on repacing this? I'v watched it done on other smaller machines. Does anyone have a clue what it would cost to hire it done? Also what would I harm running it the way it is? Thanks

Cat 345C swing gear