Thanks for your help as usual. According to the chart on my owners manual, This unit requires 36 oz of refrigerant. Will there be any problems if I put in another 12oz can of refrigerant and see what happens?

 

I got the problem solved. I went ahead and put more refrigerant in the system and as I did that, I noticed that the low pressure was ok at 40psi but the high pressure never went up pass 80psi. It was 80 degree when I was doing this so the high pressure should of been between 150 and 175psi. I took my truck to a shop here to have them remove all the refrigerant that was in the system out . While there, The tech at the shop told me I had a high pressure restriction and that it was more likely the accumulator and the orifice. He also noticed that one of the refrigerant lines was loose so he tighten it up. I brought the truck home and replaced the 2 parts and did a vacuum down on the system. After the vac.down, I left the gauges on for about 30 minutes and there were no vacuum leaks at all. I than recharged the system with 32 oz and when I did, the low pressure was at 45psi and the high pressure went up to 175psi steady, no fluctuations on the gauges at all. Its nice and cold now, right at about 40 degrees inside the cab. I also put in some dye in case I have a leak later on.
I want to thank Old Chevy for his great help in guiding me in the right direction on fixing my truck. I appreciate it very much.