Just wondering if anyone has ever compared mileage with the tow mode on or with it off. My travel trailor isn't much of a load for a duramax, so I could tow with-out the tow mode if it made better gas mileage. what's everyones thoughts??:think:

You might see slightly better mileage in the normal mode if you do a lot of running below 55 mph where the trans may tend to downshift in T/H. At steady speeds there or above you won't. Also if you accelerate from low speeds where the higher T/H shift points come into play. But, on the other side, your trans will tend to run cooler in T/H even at the lower speeds because it will lock under conditions that it would not in normal mode resulting in less slipping. Your trailer is plenty heavy enough to see these benefits.

TC

From my personal experience the MPG would be less if you are in a stop-go situation... The shift points are higher for each shift. Additionally, I notice it stays in 4th longer and has to be arround 52-55 mph before it goes into overdrive in the tow-haul mode. It also seems to anticipate that you are cruising in the gray 50 mph range and in stop-go traffic.
and does not go into OD as easily as when in the tow haul mode and at sustained 55+ highway speeds. If you are at sustained highway speeds there is no difference in MPG over tow-haul and normal.

That being said. If you are towing, particularly in stop-go traffic, I suggest you still use the tow-haul mode. In the tow haul mode, not only are the shift points better so as not to lug and stress the engine, transmission and turbo (EGT goes way up when lugging) , it also locks up the converter in 2nd through 5th. In normal only the 5th is locked. Locked in each gear the transmission runs cooler.

Awfully smart tranny, best to let it do its job.;) Under 50mph you might disengage O/D if you find the tranny searching or constantly shifting. Otherwise let the T/H mode do its thing. Later. JJ :)