What is the "ccv" mod, and what does it do , andhow do you do it. thanks

 

The CCV mod reroutes the CrankCase Vent system that in stock form vents into your intake system. That is what causes the oily residue around your intercooler boots. Most guys reroute the system to run out the rear of the truck. The best way to do it is to get about 12 feet of 3/4 inch hose, remove the CCV box on the driver side valve cover and turn it around so the outlet faces the rear of the truck, attach the hose to the outlet, and run it out towards the rear of the truck. You can leave the stock CCV vent in the air intake hose if you plug it, but it is better to just remove it, and get a 4 inch long section of 4 inch tubing and use that to replace the CCV vent.

 

Am I to assume that this CCV mod is only for 99+ PSDs?

 

No. It is for the older models also. The CCV is set up just like the 99's-03's. The intercoolers are the only difference. They still have the boots where the air goes into the engine.