Aero Exhaust AT4040XL Aero-Turbine Resonated Performance Muffler

Did exactly what I needed it to do, it quieted down a 4 inch straight pipe. Cummins high idle had a insanely loud high pitch noise before, it is much quieter at both low idle and high idle. Truck will still get loud if you get on it, but quiets down once you ease up on the engine a bit.

Awesome product! Installed on a 21 cummins. No more drone in the cab or scream in the exhaust on a cold start. Very nice tone going down the road as well.

Aero Exhaust AT4040XL Turbine Resonated Performance Muffler. Easy install, love the sound, deep throaty, powerful. Great addition to a 400 HP 5.9L Cummins Diesel, in a 2006 2500 4X4. Highly Recommend!

I put this on my 6.7 cummins and it made a world of difference! It sounds much deeper and throatier its the perfect sound if youre thinking about it go for it you wont regret it

Very high quality! Wanted to take the edge off my duramax, definitely improved tone. Believe it or not, actually increased perceived power and bumped up mileage. Engine must like some back pressure. Would buy again for sure.

Very fast shipping, exactly as described, I reached out to ask if there were clamps included, they are not, I was told lap clamps are what I need. I had already ordered some in anticipation, installed the muffler in about an hour, sounds much quieter in the cab vs the straight pipe w/o a cat. I hear a bit of drone at 55, but it’s nice. The muffler is gorgeous, funny to say about a piece of metal, but it was superbly packaged and just a shiny, unblemished muffler. Kind of saddened me, that the rest of my exhaust is galvanized. 10/10, will definitely do business with XD, again. #1288729