8 speed transmission operation

[DickLowman]

Recently while hunting I was descending an 8-mile 9 percent grade on a gravel road with continuous tight turns. Truck is 2022 Tradesman 2500, 6.4 hemi, 8 speed trans, towing 2000 pounds. I set electronic range select to 2-1 to save brakes. Going 10 - 20 mph, tach ranged between 2 and 3,000. When back on pavement with ERS reset to D, the transmission was not normal, often delaying up shift and downshifting at inappropriate times. As example, when towing 7000 pound trailer (in tow-haul) accelerating slowly from start on flat ground tach would hit 4000 before shift. Dealer found no problems but did some kind of reset that has worked. I'm guessing tranny "learned new driving pattern", but failed to unlearn. Has anyone else had this problem? Any suggestions on how to avoid in future when on challenging downgrade?

 

[Riccochet]

Not much you can do other than drive the snot out of it while unloaded so the keep alive memory goes back to a normal state.

 

[Stavinksi]

Wonder if stopping and turning off the truck for a few minutes every couple miles would help?

 

[Tulecreeper]

I use my ERS all the time and have never had an issue with it not going back to normal afterward. But then I activate my ERS every single time I get in the truck, and although I usually keep it in 8th gear and just let it do it's thing there have been a number of times I have limited the gears for a period of time and never had a problem.

 

[crash68]

As example, when towing 7000 pound trailer (in tow-haul) accelerating slowly from start on flat ground tach would hit 4000 before shift.

The Tow/Haul is supposed raise the shift points to push the engine further into the torque band, peak torque of the 6.4L is 429 ft/lbs at 4K rpms. If you were expecting to tow at 2K rpms, you should have bought a diesel. Even the SO Cummins makes more torque just above idle than the 6.4 Hemi does at it's peak. Torque is what pulls a trailer, not horsepower. This "complaint" is sorta common with people not accustomed to towing with a gas engine (or towing in general). Too low of rpms can cause the engine to lug which is a lot worse than turning a few extra rpms. The ZF transmissions are smarter than most when it comes to knowing what gear it should be in.