I own an 04 with 108K miles... We tow with it so often that we've never ran through a full tank of fuel empty... and our loads go up to 20K lbs... . I came out of Calgary Alberta Canada last week, back to Spokane with 9500 KG on the trailer axles... 20,500... we are on the OE set of brakes on the truck and use the pacbrake all the time... I actually own 6 trucks all with exhaust brakes...
At the last brake inspection we had 35% of the pads left. . with the intent to change the pads at about 115K miles before they have a chance to go into the rotors...
The pacbrake will hold up to a 15000 lb trailer down a 6% grade in either 4th or 5th gear without the service brakes... . on the larger loads some braking is required...
This truck travels a loop... . down I-5 to San Diego, to Phoenix and up I-15 to Montana back to Spokane on I-90... . 3 times across the divide... .
If you have an special questions e-mail me here or at -- email address removed --
Hope this has been some help...