Loud clicking sound

[Beaver]

Problem, When all is quiet at night we have had a loud "click" or "bang"sound the repeats itself every 5 minutes in the bedroom area. Checked for something electric, and the 50amp circurt breaker in the battery area. Though it might be the hydraulic system. Have been unable to pinpoint the source. Only thing I could determine was the hydraulic fluit was low. Moved the slides in, hooked up and raised the legs and added a quart of fluid. We then moved to a new site and the problem went away.
Anyone got any ideas what was causing the problem?? In my search I also noted one of the rear jacks had minor leaking.