Rig is level when putting slides in and out? Being out of level can cause more strain. Might help if we knew what type of RV an slides you have. If you checked voltage at the batteries did you also check at the slide motor? Also check the voltage while the motor is running. Perhaps the batteries just can't support the load anymore?
Cut it 3 times and it's still too short...
2017 Sandpiper 381RBOK
2006 Ram 3500 Cummins Dually