Gas and Oil Home Heating Furnaces - Heat Pump Reversing Valve Problem

I have a Rheem RPGA-030JAS Heat Pump with what appears to be a reversing valve stuck between the heating and cooling positions. When running the unit in either cooling or heating modes I don't get any heating or cooling at the indoor coil. The only change in refrigerant temperature seems to be an increase in temperature in the compressor inlet and outlet lines and through the reversing valve. The only problem that could cause this is if the reversing valve is stuck between the heating and cooling positions allowing the refrigerant the leak from the compressor outlet back into the compressor inlet. This would be the path of least resistance with not much flow through either coil. According the the wiring diagram when the reversing valve is energized it moves to the heating position. If the thermostat, reversing valve relay or solenoid were not working, the reversing valve should remain in the cooling position. That leaves the reversing valve itself as the only thing that could cause this behavior.

Would anything else cause a heat pump to malfunction in the above way?

Is there anyway to unstick the reversing valve (even temporarily) without removing it or disconnecting any refrigerant lines?

Thank you in advance.

to off.Take a rubber mallet and tap end of valve.NOT real hard but give it a good jolt.Set a/c to cool.Check a/c..You may have to repeat this a couple times.This will at least allow you to check valve.Hopefully this works.Other possibility is compressor valves are shot.PDF