SweetLou wrote:
Not to take away from this informative debate, but I have been curious on my 2013 6.7, the RPM in 6th seems low at 1200-1300 unloaded. Just by my ear it sounds as if it needs to be higher so I manually shift it into 5th to be around 1500-1600. Do I have an issue, and need to get something reprogrammed?
That is just how the stock 68RFE with 3.42 gears is with stock programming. Nothing wrong with being that low unloaded and the Cummins will easily lug even lower than that. I would not want to be towing 5-7k at that low of rpms though and the stock trans tuning will put you there sometimes.
I had an old trans tune on my truck that allowed it to be at 45 mph in 6th(975 rpm) and it still had enough power to slowly accelerate up hills unloaded. Only had it in my truck for about a week and switched to a better tune that kept rpms above 1,400.
