When they first made the HO those engines where great. 2004ish I think. I owned one and would have never let it go but my knee went bum and I couldn't shift anymore, it was a stick. It was sweat sounding for some reason, the turbo was so smooth. Can't say much for earlier or the newer ones. I test drove a new one and wasn't that impressed. Dunno if I had an off day or and off truck, but my impression was the older truck I had was smoother. My brother in law had two if those HO's, he had to trade it in for the exact opposite reason, he had to get a stick because he towed heavy all the time and kept burning through automatic tranny's. Great info on this site but TDR is the place to go to ask for detailed Cummins stuff as well.