Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
it does sound like your compressor is creating too much drag, this is more likely due to a failing compressor. The low freon level could have contributed to it but being low would not create drag in and of itself. Some rpm fluctuation is normal when the a/c is on as the compressor is adding a load to the engine. Can you shoot me your VIN so I can pull up the vehicle build.
The lower RPMS in reverse with it on is due to line pressure in the transmission being commanded high, It sounds like it is low on Freon however you will probably want to get it evacuated and vacuumed then remove your orifice tube and inspect it for debris.
here is the process with pictures. it does require a quick disconnect tool to remove the line where its at.
Important: Cap all A/C components immediately to prevent system contamination.
if you can get it out look for metal in the screen.
That's what it seems like so looking at that orifice tube will let us know if the compressor is actually failing. If it is you want to fix it soon so you don't have to replace that many parts because when they completely fail it can fill your ac system with a ton of metal that is hard to remove. the line pressure being high in the vehicle transmission adds load combined with the extra load from the ac it exacerbates the problem.
Evacuate the system, and replace the orifice tube(or AC filter as some will call it), it is a very cheap part so you want to replace it when you remove it, but have them inspect it for metal or debris so you can see if you compressor is on the way out.
If it has metal then replace the compressor and receiver dryer. Then check for leaks once recharged, they can add a florescent dye. If it is low we can surmise it has a small one somewhere.
That can cause excessive cycling but i suspect if this has been a worsening situation you will find metal there.