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10-23-2017, 11:36 AM
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#1
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Junior Member
Brand: Thor Motor Coach
State: Louisiana
Posts: 5
THOR #3766
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taking a steep grade downhill
I am going to be traveling east on I-24 from Manchester Tennessee this week. If you have taken your RV over Mt. Eagle Mountain, how did you take the downhill grade? Did you do it in first gear or just let the brake assist handle that steep downhill grade? I am driving a 2013 Thor 37ft class A gas MH pulling a small car on a dolly.
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10-23-2017, 11:43 AM
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#2
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Axis/Vegas Enthusiast
Brand: Thor Motor Coach
Model: Axis 24.4
State: Michigan
Posts: 9,837
THOR #1150
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Put it in tow-haul mode (press the button on the end of the shifter). On the downhill grade simply tap the break--the trans will downshift every time you do so.
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10-23-2017, 12:13 PM
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#3
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Senior Member
Brand: Thor Motor Coach
Model: 37GT
State: Florida
Posts: 809
THOR #5246
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What Jamie said, tow/haul mode all the way. In a 37' with the V-10 I would start down at around 50mph tops, the engine will soon find the right gear. When the rpm's start letting you pick up too much speed you can use a little brake to take some speed off and force possibly another downshift, just don't ride the brakes or you will eventually experience "brake fade" because they will get too hot.
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Full Time in 2017 Newmar Ventana 4369
pulling a 24' enclosed (Mini Cooper/Harley/Kayak)
(traded 2014 Thor Challenger)
US Army 70-73 Retired LEO
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10-23-2017, 01:43 PM
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#4
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Senior Member
Brand: Thor Motor Coach
Model: Hurricane 35C
State: South Dakota
Posts: 1,132
THOR #3761
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X2 for Jamie's answer. Tow/Haul is the answer.
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John
2016 Thor Hurricane 35C with pups Piper and Annabelle
2013 Ford Fiesta toad
FMCA - F457085
Blog - https://traversity.us
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10-23-2017, 02:25 PM
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#5
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I Think We're Lost!
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 22,195
THOR #8860
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x3...
Take your time, and it'll all work out fine!
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"What: me worry?"
Good Sam Member 843599689
Current coach: Tiffin Wayfarer 24 BW
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10-23-2017, 02:27 PM
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#6
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Junior Member
Brand: Thor Motor Coach
State: Louisiana
Posts: 5
THOR #3766
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That is great advice guys. I had another advise me to shift to first gear at the top of the downhill grade. They have a place to stop before heading down. What do you think of 1st gear?
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10-23-2017, 02:35 PM
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#7
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Site Team
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 14,129
THOR #7035
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Quote:
Originally Posted by brown45cal
That is great advice guys. I had another advise me to shift to first gear at the top of the downhill grade. They have a place to stop before heading down. What do you think of 1st gear?
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This is an Interstate, right? Minimum speed limit of 45 mph? In first gear?
Start at 45 mph, tow/haul mode, cruise control. At 50 mph the cruise will downshift automatically to slow you down. If that isn't comfortable you can downshift manually by tapping the brake as Jamie said.
Slow down early, slow down hard when you do brake.
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Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad - Selling
2020 Chevy Colorado Z71 Trail Runner Toad
2024 Chevrolet Trax 2RS - Soon 2B TOAD
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10-23-2017, 02:44 PM
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#8
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Junior Member
Brand: Thor Motor Coach
State: Louisiana
Posts: 5
THOR #3766
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Tfryman, thanks for information. That answers my questions.
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10-23-2017, 03:43 PM
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#9
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I Think We're Lost!
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 22,195
THOR #8860
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It's good to hear that your apprehensions have "slowed down"!
__________________
"What: me worry?"
Good Sam Member 843599689
Current coach: Tiffin Wayfarer 24 BW
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10-23-2017, 04:11 PM
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#10
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Senior Member
Brand: Thor Motor Coach
Model: ACE 29.0
State: Colorado
Posts: 219
THOR #2581
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Quote:
Originally Posted by Joe-FL
When the rpm's start letting you pick up too much speed you can use a little brake to take some speed off .
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I've never tried this as I generally set my cruise at 50 on the steep grades and forget it but I do have a couple questions on this. Does braking not drop it to yet a lower gear? Is there something in the system that prevents you from shifting down too much and over revving the engine?
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No more wasted time.
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10-23-2017, 04:38 PM
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#11
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Senior Member
Brand: Thor Motor Coach
Model: Miramar 33.5
State: Washington
Posts: 217
THOR #578
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As stated above the tow/haul mode was designed for just this situation. On my 2016 Miramar, F-53 V-10, there is no red line on my tachometer. I’ve asked the Ford technicians about the tow/haul mode and the what seemed to be very high rpm’s while descending a steep grade.
He explained to me that this is engine is de-rated so much, there was no need to place a red line on the tach. He said if I use the engine as designed under normal driving conditions, I would never have a problem.
I too was concerned with the screaming of the engine while descending a steep mountain grade, 4500 rpm’s for several minutes. They assured me the engine was designed with this in mind!
I’ve observed all engine parameters available to me while descending grades and have noticed no changes to coolant temp, transmission temp or any other parameters. She just purrs like a kitten when she shifts back into low gear!
I’m fully loaded at approx 21,800 pounds while flat towing a Honda CR-V.
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10-23-2017, 04:57 PM
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#12
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Senior Member
Brand: Thor Motor Coach
Model: Challenger 37TB
State: Kentucky
Posts: 1,032
THOR #1020
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We've been up and down Monteagle - absolutely no problem for your V10. Our coach fully loaded and pulling a 2013 Explorer is about 13 tons. If you want a real lesson, head on out to the Yellowstone Park area. Boogity Boogity!! It makes Monteagle very easy to do. Heading into the east side of Yellowstone out of Cody, or pulling the mountains up and into Ten Sleep from the east provides a graduate degree in V10 driving. Once you have the hang of it, no worries. (IMO) It is all about not hurrying up or down.
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US Army Retired - Loving The Road Trip
Challenger 37TB
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10-23-2017, 07:07 PM
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#13
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Senior Member
Brand: Thor Motor Coach
Model: Gemini 24TX (Formerly)
State: California
Posts: 1,459
THOR #5821
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Critical on any steep downgrade, never allow speed to get away from you. Decide what speed is safe and work your transmission and light braking(gasoline) DP let the Jake work its magic, do not under any circumstances pump an air brake system.
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10-23-2017, 07:27 PM
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#14
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I Think We're Lost!
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 22,195
THOR #8860
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Yup! Keep the situation under your control, and you'll never regret the results!
__________________
"What: me worry?"
Good Sam Member 843599689
Current coach: Tiffin Wayfarer 24 BW
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10-23-2017, 08:15 PM
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#15
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Senior Member
Brand: Thor Motor Coach
Model: ACE 29.0
State: Colorado
Posts: 219
THOR #2581
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Quote:
Originally Posted by Halibut214
I've never tried this as I generally set my cruise at 50 on the steep grades and forget it but I do have a couple questions on this. Does braking not drop it to yet a lower gear? Is there something in the system that prevents you from shifting down too much and over revving the engine?
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Thanks Brian, though a bit disconcerting at first I knew this was a high revving engine but I would really like to get my questions answered. If I'm already turning 5000 rpm's, hit the brake as was suggested by Joe-FL and it shifts down yet again I'm guessing one of two things are going to happen, the rear wheels are going to start skipping or the engine is going to over rev and unless there is a failsafe of some sort I guarantee you any engine can be over revved.
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No more wasted time.
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10-23-2017, 08:24 PM
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#16
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Senior Member
Brand: Still Looking
State: Texas
Posts: 6,187
THOR #2121
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The point of using brakes momentarily is to slow down enough so that when transmission does downshift one more gear, you'll be back to 5,000 RPMs or less.
It's key to remember that the lower the gear, and thus the lower the vehicle speed, the more engine braking force will be developed at wheels to prevent a runaway situation.
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10-23-2017, 08:34 PM
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#17
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Site Team
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 14,129
THOR #7035
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Quote:
Originally Posted by Halibut214
Thanks Brian, though a bit disconcerting at first I knew this was a high revving engine but I would really like to get my questions answered. If I'm already turning 5000 rpm's, hit the brake as was suggested by Joe-FL and it shifts down yet again I'm guessing one of two things are going to happen, the rear wheels are going to start skipping or the engine is going to over rev and unless there is a failsafe of some sort I guarantee you any engine can be over revved.
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If you are already at 5000 RPM hitting the brake will not downshift you to a lower gear, the ECM (computer) will not allow it.
In fact, most transmissions will automatically upshift if you crank the RPMs up with your foot, even if you forgot and left the shift lever in first or low.
__________________
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad - Selling
2020 Chevy Colorado Z71 Trail Runner Toad
2024 Chevrolet Trax 2RS - Soon 2B TOAD
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10-23-2017, 08:46 PM
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#18
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Senior Member
Brand: Thor Motor Coach
Model: ACE 29.0
State: Colorado
Posts: 219
THOR #2581
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Thanks Tfryman. I suspected there was something but the way mine winds up on a steep grade I didn't want to even try this without being reasonably sure.
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No more wasted time.
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10-23-2017, 10:20 PM
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#19
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Senior Member
Brand: Thor Motor Coach
Model: Challenger 37TB
State: Kentucky
Posts: 1,032
THOR #1020
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We've been all over the US through lots of mountains - never had a problem. Start the downgrade in Tow/Haul mode at the posted truck speed (there is reason it is posted lower than cars). In the case of Monteagle it is 35 MPH I believe. Once your coach begins to get a bit over that, I depress the brakes fairly sharply. That may cause a downshift but ofter it doesn't. Between the engine braking and the hit on the brakes occasionally, no problem.
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US Army Retired - Loving The Road Trip
Challenger 37TB
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10-23-2017, 10:21 PM
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#20
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Senior Member
Brand: Thor Motor Coach
Model: Gemini 24TX (Formerly)
State: California
Posts: 1,459
THOR #5821
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I can't believe that Ford didn't design the transmission so you can't damage the engine. Every other manufacture does.
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