The Secret to Cruise-Control on Mountain Highways
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Joined: Apr 2009
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From: Gilbert AZ
The Secret to Cruise-Control on Mountain Highways
Having put most of the 8K miles on my truck either in the San Juan Mtns of SW Colorado, or climbing up/down the Colorado Plateau to get there, I've had plenty of time to experience and figure-out the 09 Ram 1500 Cruise-Control System - ALMOST.
Given the power of the Hemi and it's willingness to rev and roar, maintaining Cruise-Control on Uphill segments is a real No-Brainer. Just pick a speed that you won't have to break until the tightest twists and turns, and you are good to go. It may downshift, if the climb requires it (if you can find a steep-enough grade it may even do a 2nd downshift - I've found a few such). And if you feel the need to apply a little extra gas pedal, Cruise Control will still be ON when you ease off the pedal. All is GOOD.
But...
Cruise-Control on downgrades is a Different Story !!
Coming from 7 years with a Dodge Dakota (which I was very happy with - except low HP of older 4.7-V8), I expected an efficient use of downshift and engine-compression to manage downhill speed. But NO...
At the top of a pass, I'd set the Cruise at a speed for which I could handle the entire downhill segment. All would be good through the point where the downshift occurs, which should increase the engine-compression braking. Instead, it would seem that the downshift would be limited to "out-of-torque-lockup" but still in final-overdrive. This, of course, provides very little additional braking effort - and we are Off-to-the-Races !! Speeds climb as the weight and the slope overcome the downshift advantage, and I am forced to apply the brake pedal. This immediately defeats the Cruise-Control and returns the transmission to high-gear, leaving me to only the brake pedal for the remainder (and the shifter - if I decide to take over the "automatic" functions) and to re-engage the Cruise manually. In the older Dakota, I'm used to the Cruise-Control taking downshifts all the way to 2nd-gear if necessary and providing great assistance in speed control even if at high-revs.
I found the Cruise-Control / Transmission Control system to be rather lacking on downhill runs !!
The solution is the Tow/Haul-mode !! It provides the functionality and control that I'd have expected from Cruise-Control (or from a combo of the two systems). Reach over and engage the button on the center console. Then, as you first drag the brakes in order to control your speed, the Tow/Haul-mode will perform a REAL speed-based downshift - AND hold it even after you lift your foot from the brake. It will even force a 2nd downshift if you brake hard enough or the downhill acceleration pressure is strong. It will even continue this action through at least minor additions of gas pedal, if your speed drops too low. You simply need to remember to disengage at the bottom of the downslope, so that Tow/Haul-mode doesn't apply it's Overdrive-lockout once on flatter ground.
Real, Effective, Useful !! Why in the world didn't the Dodge Engineers integrate Tow/Haul-mode into the Cruise-Control System ??
Anyone else seeing different effects ??
Given the power of the Hemi and it's willingness to rev and roar, maintaining Cruise-Control on Uphill segments is a real No-Brainer. Just pick a speed that you won't have to break until the tightest twists and turns, and you are good to go. It may downshift, if the climb requires it (if you can find a steep-enough grade it may even do a 2nd downshift - I've found a few such). And if you feel the need to apply a little extra gas pedal, Cruise Control will still be ON when you ease off the pedal. All is GOOD.
But...
Cruise-Control on downgrades is a Different Story !!
Coming from 7 years with a Dodge Dakota (which I was very happy with - except low HP of older 4.7-V8), I expected an efficient use of downshift and engine-compression to manage downhill speed. But NO...
At the top of a pass, I'd set the Cruise at a speed for which I could handle the entire downhill segment. All would be good through the point where the downshift occurs, which should increase the engine-compression braking. Instead, it would seem that the downshift would be limited to "out-of-torque-lockup" but still in final-overdrive. This, of course, provides very little additional braking effort - and we are Off-to-the-Races !! Speeds climb as the weight and the slope overcome the downshift advantage, and I am forced to apply the brake pedal. This immediately defeats the Cruise-Control and returns the transmission to high-gear, leaving me to only the brake pedal for the remainder (and the shifter - if I decide to take over the "automatic" functions) and to re-engage the Cruise manually. In the older Dakota, I'm used to the Cruise-Control taking downshifts all the way to 2nd-gear if necessary and providing great assistance in speed control even if at high-revs.
I found the Cruise-Control / Transmission Control system to be rather lacking on downhill runs !!
The solution is the Tow/Haul-mode !! It provides the functionality and control that I'd have expected from Cruise-Control (or from a combo of the two systems). Reach over and engage the button on the center console. Then, as you first drag the brakes in order to control your speed, the Tow/Haul-mode will perform a REAL speed-based downshift - AND hold it even after you lift your foot from the brake. It will even force a 2nd downshift if you brake hard enough or the downhill acceleration pressure is strong. It will even continue this action through at least minor additions of gas pedal, if your speed drops too low. You simply need to remember to disengage at the bottom of the downslope, so that Tow/Haul-mode doesn't apply it's Overdrive-lockout once on flatter ground.
Real, Effective, Useful !! Why in the world didn't the Dodge Engineers integrate Tow/Haul-mode into the Cruise-Control System ??
Anyone else seeing different effects ??
Veteran
Joined: May 2009
Posts: 482
Likes: 1
From: Texas
expect future trucks to completely turn the motor off when enough kinetic energy is available.
Veteran
Joined: May 2009
Posts: 482
Likes: 1
From: Texas
i don't want to cross contaminate threads here, but going back to your mileage thread response, i find the mileage difference is significant with the cruise control engaged.
there is at least a 2 mpg (more with shorter trips or grade differences) decrease with the cruise engaged with my truck.
there is at least a 2 mpg (more with shorter trips or grade differences) decrease with the cruise engaged with my truck.
Last edited by jawsdc; Aug 3, 2009 at 01:15 PM.
Rookie
Joined: Mar 2009
Posts: 86
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From: Danville, KY
seigell
I am with you on this one. I don't know why you have to engage the Tow / Haul mode to have it work properly. My 2003 Ram has the most consistent cruise you have ever seen. It is almost too good. It will not let the speed vary more than 1 MPH before it takes control and that is uphill or downhill regardless of what mode the tranny is in. I find myself hitting cancel on slight downhill grades where the roads are relatively straight so that it does not downshift.
I am with you on this one. I don't know why you have to engage the Tow / Haul mode to have it work properly. My 2003 Ram has the most consistent cruise you have ever seen. It is almost too good. It will not let the speed vary more than 1 MPH before it takes control and that is uphill or downhill regardless of what mode the tranny is in. I find myself hitting cancel on slight downhill grades where the roads are relatively straight so that it does not downshift.
