2002 f250 crew cab, 7.3 PS - Couple weeks ago will climbing a somewhat steep grade the ac started blowing warm air. It blew warm climbing every grade but once at the top and traveling downhill, the ac came back somewhat. 90-100 ish degrees. I live at 5000ft elevation. Haven't touched the ac until now. All hoses and connections are clean with no visible leakage or weathering at all. I charged the system with ac pro and it did get a bit cooler but still blows hot air under load while climbing a grade. Condenser is clean as I live in the north and we don't really have the bugs that back east will see clogging the condenser. I removed a shim from the ac clutch as it did have close to .050 clearance. One problem I seen online was the ac blowing out the defrost which I do Not have that happening. I did see another person mention the exact problem I am having but they did not receive any answers or suggestions. Any suggestions greatly appreciated! GK86