This weekend I came down Eisenhower pass w of Denver for 8 miles with the exhaust brake on. A few miles after resuming normal driving conditions I noticed a different exhaust tone coming from the unit and when accelerating from a stop a high pitched whistle at the exhaust witch would mellow out as the unit shifted gears. All functions of the engine, Xmission, etc and gauge readings are normal and the exhaust brake functions works as always.
It is my belief that a baffle or something has seperated or let go in the muffler? Has anyone any other thoughts that might cause this problem other than the muffler?
03 Horizon 32T with 5.9 ISB Cummins 16,000 miles.