Controlling Speed on Steep Grades
Cargo Master
Joined: Feb 2004
Posts: 2,061
Likes: 167
From: Central Texas
I use "M" exclusively when towing our nearly 10k lb camper. I do not like T/H at all except for braking and I still don't use it. With my 6.7 I can do everything I need between 1000 - 2000RPM.
Moderator
Joined: Jul 2011
Posts: 6,509
Likes: 658
From: Sioux Falls Area
You guys don’t know how lucky you are to have manual mode available.
no manual mode or ability to select gears on expedition until 2015. Just “D” with tow/haul and “3-2-1” for steep hill descents.
honestly, with his truck and trailer he shouldn’t even have to think about it. He’s towing the same as me with a much more capable vehicle. It really should be a pleasant towing experience with his combo.
no manual mode or ability to select gears on expedition until 2015. Just “D” with tow/haul and “3-2-1” for steep hill descents.
honestly, with his truck and trailer he shouldn’t even have to think about it. He’s towing the same as me with a much more capable vehicle. It really should be a pleasant towing experience with his combo.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,350
Likes: 5,945
From: Lake Hartwell, GA
- Start down the hill at a slower speed. At the top, be going the speed you want or slower.
- Brake in short bursts, not long drags. I tell my wife to set a personal limit, stab the brakes to 5 - 10 MPH below that when braking and repeat.
- Use a lower gear at an appropriate RPM. Don't use a lower gear a high RPM because you may not leave yourself room for error.
- Use your brake controller plunger if you need to.
- Upgrade to disc brakes on the trailer if needed.
Basically, slow down, gear down and short bursts with braking.
5th Wheeling
Joined: Jun 2021
Posts: 47
Likes: 16
I recently completed a 4350 mile New England trip. In Pennsylvania we had quite a few steep grades,, both uphill and downhill. Uphill presented no challenge, but I am hoping someone out there can provide me with some best practices in how to maintain control of speed on steep downhill grades (steeper than 4-5%).
Rig:
2020 Ford F-350 7.3L with 10-speed transmission and 3.73 rear axle and 11300# GWVR Package
Grand Design 2500RL bumper-pull - dry:weight: 5,857 (GWVR 7,495). Hitch Weight 581
Equalizer weight distribution/anti-sway hitch
Towing with Tow/Haul mode engaged always.
For grades around 4% we just kept the truck in cruise and the engine/transmission shifted and took care of the speed with no problem.
Issue was on very steep grades - the type where they have the “check your brakes” sign at the top. What is the best approach?
1. Use cruise control at a slow speed?
2. Apply breaks and let the tow/haul mode downshift?
3. Use the shift lever to “M” and use the button to downshift?
The worst case we had was in upstate NY - a half-mile extremely steep downhill with a stoplight at the bottom. We crawled down at 30 mph using approach #2. I think we were in 2nd or 3rd gear on our 10-speed transmission.
Again - looking for best practices based on knowledge of how te engine and transmission work in tow-haul mode.
Thanks!
Warren
BTW - that 7.3L and 10 speed transmission combination was awesome - a real beast! We stayed in cruise most of the time.
Rig:
2020 Ford F-350 7.3L with 10-speed transmission and 3.73 rear axle and 11300# GWVR Package
Grand Design 2500RL bumper-pull - dry:weight: 5,857 (GWVR 7,495). Hitch Weight 581
Equalizer weight distribution/anti-sway hitch
Towing with Tow/Haul mode engaged always.
For grades around 4% we just kept the truck in cruise and the engine/transmission shifted and took care of the speed with no problem.
Issue was on very steep grades - the type where they have the “check your brakes” sign at the top. What is the best approach?
1. Use cruise control at a slow speed?
2. Apply breaks and let the tow/haul mode downshift?
3. Use the shift lever to “M” and use the button to downshift?
The worst case we had was in upstate NY - a half-mile extremely steep downhill with a stoplight at the bottom. We crawled down at 30 mph using approach #2. I think we were in 2nd or 3rd gear on our 10-speed transmission.
Again - looking for best practices based on knowledge of how te engine and transmission work in tow-haul mode.
Thanks!
Warren
BTW - that 7.3L and 10 speed transmission combination was awesome - a real beast! We stayed in cruise most of the time.
Moderator
Joined: Jul 2010
Posts: 12,050
Likes: 1,549
From: Media PA
You guys don’t know how lucky you are to have manual mode available.
no manual mode or ability to select gears on expedition until 2015. Just “D” with tow/haul and “3-2-1” for steep hill descents.
honestly, with his truck and trailer he shouldn’t even have to think about it. He’s towing the same as me with a much more capable vehicle. It really should be a pleasant towing experience with his combo.
no manual mode or ability to select gears on expedition until 2015. Just “D” with tow/haul and “3-2-1” for steep hill descents.
honestly, with his truck and trailer he shouldn’t even have to think about it. He’s towing the same as me with a much more capable vehicle. It really should be a pleasant towing experience with his combo.
Lol, at least you have Tow/Haul available, I'm dragging a 12K TT and only have the OD Off button then have to start moving the shift lever to drop gears. Pick a suitable lower gear, short sharp braking applications to control speed within a 5/10 MPH target range and enjoy the scenery.
Tuned
Joined: Sep 2018
Posts: 385
Likes: 19
With that truck and trailer combination, I'm surprised you're having any issues at all. You should be able to use tow/haul mode, press the brake a the top of the hill to scrub some speed and the truck should downshift on it's own and hold the trailer back. As stated above, manual mode works well if you need to force the truck to do something like hold a lower gear on an extended downhill run.
Tuned
Joined: Jan 2001
Posts: 312
Likes: 73
Other observations/comments:
1. Use cruise control - this approach resulted allowed too much increase in speed during the descent. Then when I braked the cruise goes off and I was stuck with #2 too late in the game.
2. Apply breaks and let the tow/haul mode downshift - I think if I would have done this before the descent it would have worked better. Since I braked during the descent, the downshift sent the RPMs skyrocketing.
The Manual approach done at the right point in time seems like the strongest approach.
Warren
Tuned
Joined: Jul 2021
Posts: 372
Likes: 199
From: NE Oklahoma
The skyrocketing RPM's is what catches me off guard. This happened anytime I was going down a descent and then started braking here and there. Next thing I know it's winding up and I'm getting stressed out. I couldn't figure out how to get it back out of that lower gear accept to accelerate again and fool the truck into thinking the descent was over.
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5th Wheeling
Joined: Sep 2021
Posts: 38
Likes: 10
From: Florence, Oregon
The skyrocketing RPM's is what catches me off guard. This happened anytime I was going down a descent and then started braking here and there. Next thing I know it's winding up and I'm getting stressed out. I couldn't figure out how to get it back out of that lower gear accept to accelerate again and fool the truck into thinking the descent was over.
Hotshot
Joined: Oct 2015
Posts: 19,694
Likes: 12,819
From: Wyoming
You don't have to accelerate. At any time, you can simply deselect the tow/haul mode and this will allow an upshift. Prior to doing this you should lock out the appropriate high gear(s) so you can control the descent. If you are not in tow/haul you can brake without the transmission downshifting. Once at the bottom, engage the tow/haul again.
Moderator
Joined: Jul 2011
Posts: 6,509
Likes: 658
From: Sioux Falls Area
The skyrocketing RPM's is what catches me off guard. This happened anytime I was going down a descent and then started braking here and there. Next thing I know it's winding up and I'm getting stressed out. I couldn't figure out how to get it back out of that lower gear accept to accelerate again and fool the truck into thinking the descent was over.
if the Rpms are higher than you want, stab the brakes hard to slow down and then let it hold a lower speed down the hill.
just remember to let them cool down after you stab them. Let them cool down for at least as long as you had them applied. Then just maintain a 5mph +\- window from the speed you want to go.
Gasoline engines are fine in the 4000-5000 rpm window. Don’t let it stress you out. That is their happy place.
Hotshot
Joined: Oct 2006
Posts: 10,147
Likes: 7,975
From: Texas
Until you learn your loads and truck and how all things react together, just select a gear that will hold you at the truck speed limit signs. No muss, no fuss, no stress, unless you are going to stress about the dipstick behind you. If he would have gotten his azz out of bed sooner he would have been in front of you……..his own fault…….not your problem.
