On-Off performance

[3176CATPOWER]

Have 11,000 miles on the Duramax and since 8,000 miles have noticed at times it takes more pedal action and more RPM to shift up to next gear.Been watching tranny temps (about 150 degrees)and see no correlation their.Engine temps show nothing much of a diff either may be a bar or greater lower than 210 degrees other than two bars below 210 degrees.Seems the longer it runs (30 miles or more)the more it wants to rev before shifting up to next gear.This truck will go like a scalded cat if you push the pedal hard enough but I like the easy into the pedal shift at 1800 RPM and accelerate briskly up to next gear that it does less often now.Changed fuel filter saw no differance and tried Standayne fuel treatment with no differance.Have also noticed more diesel clatter since 8,000 miles, maybe my hearings getting better!I wonder if the under hood temps have anything to do with this or maybe the APP (ACCELERATOR PEDAL POSITION).Took it to dealer and they scannded the ECM showing no codes.Any else seeing these symptons?

[DmaxMaverick]

3176CATPOWER

I've found that Outside Air Temp (OAT) makes the most difference of all the environmental effects. The intercooler is more efficient with cooler air, and less with hotter air. Hot OAT means hotter inlet air, and less effective cooling at the intercooler. Running the A/C is a double effect. The compressor draws power from the motor, and heats the air before it hits the intercooler. If you have your HVAC control on recirc, then the compressor is running intermitently. Try factoring these things into your calculations. Perhaps you can find your correlation. Cheers