This is my second duramax and fuel pumps keep me up at night. Ha ha. I hope I never have to experience that headache. On a side note I’m a past master of Everett Lodge #524 in PA.My 17 L5P has 240k on it. Had some DEF sensor issues, one broken drivers side manifold bolt (nightmare), cp3 fuel pump went out, And also replace the turbo which it didn't need.
Do you allow the computer to down shift for you in tow/haul? I talk the trans out of Drive and manually shift it with the shift lever. With the exhaust brake on I can shift butter smooth manually where as when I have it in Drive and touch the brakes it will down shift two gears at a time, not to my liking.My 2021 has been an awesome truck. My only complaint is it downshifts a little to aggressive with a sub 10K trailer in the tow/haul mode.
I will try this over the weekend and let you know. I don't mind shifting gears manually but I hate how the computer downshifts on its own as well.Do you allow the computer to down shift for you in tow/haul? I talk the trans out of Drive and manually shift it with the shift lever. With the exhaust brake on I can shift butter smooth manually where as when I have it in Drive and touch the brakes it will down shift two gears at a time, not to my liking.