At 003:06:38.9, the CSM was separated from the S-IVB stage and onboard television was initiated at 003:09 for about 72 minutes to show the docking, ejection, and interior and exterior views of the CM. Transposition and docking with the LM occurred at 003:19:08.8. The docked spacecraft were ejected from the S-IVB at 004:01:00.8, and an 80.2-second separation maneuver was initiated by the S-IVB auxiliary propulsion system at 004:18:00.6.

On previous lunar missions, the S-IVB stage had been maneuvered by ground command into a trajectory such that it would pass by the Moon and go into a solar orbit. For Apollo 13, the S-IVB was targeted to hit the Moon so that the vibrations resulting from the impact could be sensed by the Apollo 12 seismic station and telemetered to Earth for study.

A 217.2-second lunar impact maneuver was made at 005:59:59.5. The S-IVB impacted the lunar surface at 077:56:40.0. The seismic signals lasted three hours 20 minutes, and were so strong that the Apollo 12 seismometer gain had to be reduced to keep the recording on the scale. The suprathermal ion detector recorded a jump in the number of ions from zero at impact to 2,500 and then back to zero. It was theorized that the impact drove particles from the lunar surface up to 200,000 feet above the moon, where they were ionized by sunlight. The impact point was latitude 2.75° south and longitude 27.86° west, 35.4 n mi from the target point and 73 n mi from the Apollo 12 seismometer. At impact, the S-IVB weighed 29,599 pounds and was traveling 8,465 ft/sec.
Apollo 13

The ringing was sometimes interpreted as a hollow or glassy moon.