Q: my car makes a sound like rocks rolling when i place car into drive cannot hear when in park on under load

It seems you have two separate problems. The "rocks rolling around a tin can" sound is most commonly from the exhaust system. Possibly a broken / loose baffle in the muffler or resonator. Most commonly would be a heat shield on the front pipe or catalytic converter. The heat shields are generally two pieces that are spot-welded together around these components. With age and mileage, the welds can break or rust, causing the two pieces to rattle together. It can be random - certain gears, certain load, etc, or it can be continuous. A certified technician can assess the rattling noise to determine where exactly it is coming from.

As for the occasional stalling, any number of ignition or fuel related components can cause this. Worn spark plugs, low fuel pressure, vacuum leaks, etc, can cause stalling, either consistently or randomly. However, random faults can be difficult to assess unless they are happening at the time of inspection. However, a technician may be able scan the system to check for faults or sensor values that may be out of specified ranges, that can cause the vehicle stalling