Originally Posted by 17Racer
Thank you Delco bobby for your input. I have read the Chevy manual and just wanted to touch base on the newer six speed trans and the options given for downhill driving.
This is what I feel the owner’s manual is saying and just wanted to verify that I am understanding it correctly:
For more or less straight down hills were speeds can be controlled by the “Normal Mode Grade Braking”. Which would mean using regular drive selection with cruise control set to speed wished. And with the Tow/haul selection made to add to the effect if needed. I believe the normal mode grade braking is dependent on the cruise being set to the speed desired.
For steeper grades were slowing down for road conditions is mandatory it would be best to use “Manual Mode” to select the highest gear that can be used on the fly and without the cruise control. And this would not give you the automatic grade braking as above. Tow/haul could be used to increase the effect if needed.
I thought it was a simple question and I realize the importance of reading the manual. But I cannot say I never made a mistake in reading some instructions and thought better to check out the details on the Chevy six speed before testing on a steep downgrade. That is why I emphasized Chevy six speed and clearly stating using regular drive verses manual mode. Wanted trans information as this trans offers different options.
I just read the manual on this again. It could be made clearer.
I have the 6 speed trans on my 2013 2250 Sunseeker on a 2012 Chevy 4500 Express Van chassis.
It seems to me that the "range selection mode" offers the option to limit the highest gear used. From the manual, "The Range Selection Mode helps control the
vehicle's transmission and vehicle speed while driving down hill or towing a trailer by letting you select a desired range of gears." (Excuse the formatting)
The manual does recommend using the tow/haul mode for downhill driving. I believe this is also referred to as "grade braking." If I understand this correctly, grade braking is not available if the range selection mode is activated.
I believe that the "manual mode" discussed is referring to the 4 speed transmission.
Personally, I would deactivate cruise control on steep downhill sections. I don't think we have an interactive cruise control as some of my recent cars have had. Your vehicle is newer and that may have been added.
I also don't like cruise control on some uphill legs because when the trans downshifts my speed may increase as much as 5mph before I cancel it. this happened on a recent trip on Interstates. I had to cancel the cruise control or ram the vehicle in front of me. My cruise control was set for 65 but I hit 70 before cancelling.
Anyway, I hope this reply makes sense.