Noise under acceleration

Posting this to the Freightliner forum as well...I am a new forum member owing 3 2007 Freightliner CL120s.

One of my 3 trucks with 610K miles has a new Turbo charger installed 6 months ago. Engine is DD Series 60, 14 ltr, setup for 525HP/1650 lb-ft torque. My driver reports hearing a new noise today ONLY if the unit is under fairly hard acceleration. Noise appears to be coming from the exhaust/EGR and/or engine control items. It is not a fan, bearing or H2O pump issue. Also is not the Air pump or PS items... Driver reports no problems with developing power. Oil consumption is normal. There is no abnormal stack smoke either under any power condition. Starts fine/idles fine. Under constant speed, engine sounds "normal". However, if the tractor is pulling a hill using extra "foot" throttle, or if the speed control causes the engine to produce more power, a fairly severe "rattle" or loud abnormal "noise" is heard. When acceleration stops or load is overcome by speed or flat ground, noise goes away... Could this be an EGR valve problem? I am at or near Oklahoma City today and wonder if I can "limp" back to Mesa Arizona to repair and/or diagnose... As it is Sunday, I have no ability to read any engine computer codes or see a technician. All suggestions or similar solutions found are welcome. Thanks, Clivusmul/RBJ Mesa, Az