Hill Climbing
Just want to run this by some of you, at the present time when I climb a (Hill or Mountain) I let the Allison do the changing or down shift as needed, if it don't down shift at 1400 RPM I will down sh...
Forum Discussion
2oldman wrote:wolfe10 wrote:When you're already on a hill and your tranny needs to shift, that's more stress than anticipating the hill and shifting sans load. Kinda like downshifting a bicycle derailleur before a hill, because once you're on it, it's pretty hard.2oldman wrote:Would like more information on that one-- this is an Allison 3000 series.
Downshifting before the hill is easier on the tranny.
That said, perhaps the Allison etal are really good at shifting under load and it doesn't really matter. I remember my F450s tranny was not a smooth shift under load.
As posted, the Allison is a VERY robust transmission.
Second, there is less stress on it/less HP being generated at peak torque RPM at WOT (wide open throttle) than at higher RPM at the same throttle position. And while climbing, whether on cruise or manual throttle, it will very quickly go to WOT on a grade.
I agree with you, driving a gas rig, particularly one with a high RPM engine such as the very good Ford V10 is VERY, VERY different than a large displacement, turbo, inter-cooled diesel with Allison transmission.
Both Caterpillar and Cummins KNOW that the way to climb a grade using the least amount of fuel is at or just above peak torque RPM even at WOT. And they can sustain that for HOURS (as long as they do not overheat).
