SOunds like a dumb question but I'd like some adult supervision.
Truck is a 2003 with NV5600, I've put 10,000 miles on it running empty.
I try to shift around 1600 RPMS and generally keep it below 2000 as per the advice to get the best MPG
But I bought it to tow and today I took my 7500 lb travel trailer for a spin. The truck seemed happier shifting above 2000 RPMs and I don't know what I'm doing and figured there might be some advice here on the best technique for shifting with a load.
That's the way I tow my aluminum TT. For general purposes solo shifting between 1700-1900 is what I tell others if they drive mine. 2300-2400 is a good target for towing. Both number sets are for flat terrain. Don't hesitate to use near redline (2900-rpm HP peak) when it calls for it, but don't worry too much about the rpm at which it comes back in. "Ideal" (for power) is to come back in near peak torque (1400), but in practice this is not so easy with a difficult load and terrain challenge. Coming back in just above peak torque is the surface goal, but do NOT fixate on it. It is equivalent to racing, and that is counterproductive [as discussed below]. This is a subject wih depth, so I'll have to go on to some length.
The real trick to these is how to time the shift
: Throttle let-off, time spent in neutral, and re-engagement. IOW, be aware that the gear shift can be broken into components to think about. Don't be afraid to take on a learning curve. Believe me that shifting one of these with an oilfield load takes time to get used to (gross combo weight above 30k).
As to FE: I believe in utilizing "best habits". That is, I drive solo the way I drive when towing. This is mainly a matter of following distances, but how to accelerate, how to shift (beyond rpm chosen to pull out) and what to listen for (which is feel as well as sounds) keeps the two closer together. This is the real, the deeper
goal: To be consistent no matter the challenge faced by the truck.
Solo driving is not the default approach, if one is serious. Its sort of like horsepower numbers. They're sort of meaningless if the engine build is correct for the application. Other things are more important. So with an overall approach to driving one of these for longest life with greatest reliability with the ability to do the greatest amount of work at the lowest fuel burn
then smooth consistent shifting is the goal. Actual rpm -- where to take it out & where to put it in -- is not as important.
So, in the lower gears (through third) I shift sooner (lower) and once in Fourth start to wind it out (as when needing to merge onto a highway) and only stand on the turbo in Fourth and/or Fifth. (Which is something else to limit, in general: MAP). In a big truck this is known as progressive shifting. Less time spent in lower gears is conducive to both acceleration and FE. Keep longevity and reliability at highest and FE will fall in place.
Fastest time through the gears is the way you drive your braggart in-laws pickup. Not yours. Turbo life, injector life, clutch life, tire life and transmission life are extended by doing the very least
to accomplish a particular goal. As an FE measurement is the number
of both acceleration and deceleration events, to limit them is the gauge -- number of events as well as duration & pressure [steering: degree + number thereof]).
Okay, an example: I may run down an Interstate entrance ramp and not hit much more than 45-50 if the traffic is light and I need neither
accelerate harder or brake to enter the lane ("merging" properly is not cutting off another with less than 500' between him and you; if he has to hit brakes or shift lanes involuntarily you
are in the wrong; have failied to yield ROW) and I can then can ease on up to the travel speed of 58-mph / 1,725-rpm. IOW, as soon as I am far enough onto the ramp to determine my strategy (what my mirrors tell me), my tactics of shifting are adapted to using the least to accomplishing the most. The "rule" in this instance is to have the cruise control on ASAP (reference is both KENWORTH and CUMMINS: Time spent on cruise is directly related to highest FE). I've been known to have it on well before leaving the acceleration ramp. All traffic dependent of course (and, weather, load, etc).
Conversely, I have to on occasion push past 75-mph to then brake and merge
as all vehicles can decelerate faster than they can accelerate. A hard acceleration is on occasion called for. Overshoot the travel speed number (and I don't exceed 75 even on 80-mph Interstates and only then on the ramp alone [if I can]
as stopping a combined rig is never easy, nor is maneuvering [there is more room on the ramp than on the road]) as soon as possible. If this means running the frontage road over its' speed limit then I may do so. I still try not to get on the turbo before Fourth. Etc. Be decisive. Do not try to wait
to see if a space opens. And keep braking to an absolute minimum time!!
The slack in the hitch lash-up is high at this point.
Somewhat off topic is how to exit an Interstate. I put the signal on at least a quarter moel out. And hit the exit ramp at around 50-mph. And use the exit ramp speed limit
bracuse one wants to be accelerating slightly
onto the service / frontage road if there is no stop or tight turn. This takes the slack out of the combination which is crucial
To back into this yet further is to trip plan so as to choose a fuel stop that is in my direction of travel AND beyond any stop signs/lights prior to the Interstate ramp. This kind of approach helps offset getting into the turbo, etc, when I have to.
The Zen approach is mindfulness
. Those of us pulling 35' travel trailers and averaging
14-16 mpg have choices as when to fuel (80% of 35/gls is 28/gls) thus a 400-mile towing range makes it easy to use GOOGLE maps "Street View" to determinei n advance the day before those best fuel stops (which is also ingress/egress ease). One also knows the exit problems beforehand. Etc.
becomes a habit if desired. Control what you can, IOW, and practice, practice, practice.
5600 reference. Note discussion on longevity, thus, shift strategy over the long term.