Its my 3rd summer to own the truck, and its needed 1 can of freon at the beginning of each. However, I've noticed since its gotten hotter outside when I turn the AC on, it makes a loud "Thud" or "clunk" when the compressor kicks on. What's odd is it only does it after pressures have built up an its run a while. When you first turn the AC on when the truck is first cranked, the compressor quietly cycles on. My High pressure is 220 an low 32 at 88 degrees with a fan blowing into the grill after the single can of freon I just put in. Any ideas what that sound could be? My vent temps are right around 50 degrees.

 

My 1998, 2003 and current 2007 all do that. Does not seem to affect cooling. also will do it on defrost cycle in winter as the ac compressor cycles there too - oh I see you live where you possibly do not use defrost!!

 

Mine thuds too. Sounds like someone kicks the underside of the truck. Has done it for the entire 4yrs I've had it.

Hey DodgeChallenger, we use the defrost here at least a couple days in the year