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Old 02-14-2015, 08:51 PM   #1
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Safest way to go down steep grade with V10 CA

Need some driving help with our MH. What is the best and safest way to go down a steep grade with a Class A V10 22,500 F53 and a 4,000 toad behind it. Let's say it's a 8 deg. slope and a speed limit of 55mph. Brake buddy in the toad, so I'm not looking at suggestions on the toad but more concentrated on the V10. Rpm, speed, gear, and braking at what speeds. What rpm should I try to keep the V10 at and should I down shift at any time? At what rpm do you recommend braking to decrease the rpm. How do you recommend the braking, hard, pumping. Don't want to over heat the brakes or over rev the eng. Please if you have personal experience with the V10 respond.
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Old 02-14-2015, 09:19 PM   #2
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FWIW I start slow at the top, kick it into tow haul mode at the beginning and down shift if it's a long hill. I use the brakes intermittently on straight stretches and do not exceed a speed I am comfortable with. Steep is only part of the equation. Is it a long straight run or twisty with a stop sign at the bottom? Too slow is better than too fast. I don't redline the engine but higher revs help as long as they are not too high. If it's a long straight run I up shift as I get near the bottom and let it pick up speed using gravity. If there is any chance I will need to stop or maneuver at the bottom I stay slow all the way.
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Old 02-14-2015, 09:19 PM   #3
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Go down in at the same speed and transmission gear as you would go up that same grade. If speed builds up the "stab" the brakes to bring the speed down, then let them off to cool and repeat as necessary. DO NOT "ride the brakes, let them cool between applications.
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Old 02-15-2015, 09:44 AM   #4
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+1 on the previous 2 posts. It's better to be going slow down the hill than trying to keep control at the bottom of the hill. Especially with a 4000lb Toad pushing you down the hill. The braking recommendation by Mr_D is also a must with the F53 Chassis.


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Old 02-15-2015, 11:50 AM   #5
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I agree with all of the above. If the down grade is 7 or 8 % , at the top I will manually shift the transmission into 3rd, or even 2nd gear at a low speed and when let the engine RPMs climbs up to about 4000 , apply brakes to quickly bring RPM back down to 3500 or less, and keep repeating this down the hill. If the RPM keeps rising back up 4000RPM too quickly, then maybe a lower speed and lower gear has to be used. Don't shift down at too high a speed or the engine RPM could go too high and into the RED possibly damaging the engine. Do this early at the top and at a slow speed. Keep 4 way flashers on. If I'm behind a slow moving truck also decending slowly, I will stay behind him even if it's bit slower than I would like, I would rather go slower. Don't allow you speed to climb to the speed limit or higher until you see the bottom is close at hand. If it's a tight winding downhill grade where 20 to 25 MPH is the speed needed to handle the RV safely, I have manually geared down to 1st. gear and 3500 to 4000 RPM to keep from over using or riding the brakes. Some may say 4500 RPM is OK for the high RPM limit with the Ford V10 and it probably is, but I would feel uncomfortable with anything higher than 4500RPM.
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Old 02-15-2015, 11:59 AM   #6
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Like others, I start slow at the top. I have an overdrive gear that gets switched off first thing. I typically ride that down in that third gear. If it is really steep, then I choose 2nd gear instead.
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Old 02-15-2015, 12:08 PM   #7
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You can get down the hill many times going too slow but only once going too fast.

Experience will help you learn the capabilities of the MH. You will find you will learn what you can do to get down the hill safely.

Dont ride the brakes. Step on them smartly and slow down then leave the brakes off and the engine and transmission retard the unit. If you are picking speed up too quickly slow down at least a 1000 - 1500 rpm and then shift down another gear.
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Old 02-15-2015, 03:35 PM   #8
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As mentioned previously put the transmission in the Tow/Haul mode and start at a reasonable speed down the hill. When you reach the speed you're comfortable driving let it coast. If the hill isn't very steep you'll slow down and need to apply some pressure to the accelerator to maintain speed.


If you start to gain speed apply the brakes firmly for a few seconds then release the pedal. The transmission and engine braking will attempt to maintain the speed you slowed to. If the vehicle can't maintain the speed in the current gear it will shift to the next lowest gear about a second after you release the brake pedal.


If you want to slow down even more depress and release the brake pedal again. About a second after you release the pedal the transmission will shift down another gear. The transmission will shift down another gear each time you depress and release the brake pedal until you're in 1st gear or the engine speed will be above the maximum RPM limit when shifting to the next lowest gear.


Keep in mind the engine can go between 4,200 and 4,500 rpm on the tachometer. At those speeds it will really scream, but do no damage.


Personally I don't like the engine screaming at those RPM's so I rarely let it go over 3,800 rpm. If I need to apply the brake more than once or twice going down a hill I usually take it out of the Tow/Haul mode long enough to apply the brakes long enough to reduce the speed about 10 mph. Then put it back in Tow/Haul and let the engine/transmission combination try to maintain the selected speed.


Keep in mind when decelerating or coasting in the Tow/Haul mode the transmission will downshift (if possible) about a second after each time the brakes are applied and released.
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Old 02-15-2015, 09:11 PM   #9
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Thanks for all the input I'm taking it in. Gordon you put it best.
You can get down the hill many times going too slow but only once going too fast!
We're headed to AK in June is why my post.
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Old 02-15-2015, 09:19 PM   #10
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The steepest grade we ever encountered was going west out of Jackson Hole. 5 miles of 10% up and 5 miles of 10% down. Had a Type C MH with the 460, towing a '95 Honda Odyssey on a dolly with surge brakes. Burned the brakes out on the dolly but I sure was glad to have them!
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Old 02-15-2015, 09:23 PM   #11
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Quote:
Originally Posted by GREGORYJ View Post
I agree with all of the above. If the down grade is 7 or 8 % , at the top I will manually shift the transmission into 3rd, or even 2nd gear at a low speed and when let the engine RPMs climbs up to about 4000 , apply brakes to quickly bring RPM back down to 3500 or less, and keep repeating this down the hill. If the RPM keeps rising back up 4000RPM too quickly, then maybe a lower speed and lower gear has to be used. Don't shift down at too high a speed or the engine RPM could go too high and into the RED possibly damaging the engine. Do this early at the top and at a slow speed. Keep 4 way flashers on. If I'm behind a slow moving truck also decending slowly, I will stay behind him even if it's bit slower than I would like, I would rather go slower. Don't allow you speed to climb to the speed limit or higher until you see the bottom is close at hand. If it's a tight winding downhill grade where 20 to 25 MPH is the speed needed to handle the RV safely, I have manually geared down to 1st. gear and 3500 to 4000 RPM to keep from over using or riding the brakes. Some may say 4500 RPM is OK for the high RPM limit with the Ford V10 and it probably is, but I would feel uncomfortable with anything higher than 4500RPM.
That's my exact procedure. At 4,000 rpm I hit the brakes hard for about 3 to 5 seconds and then let off.

I love getting behind slow trucks...then they get the blame for the slow speed.
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Old 02-16-2015, 06:11 AM   #12
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The road in and out of Skagway Alaska is a 12% grade for 12 miles. We didn't have any troubles getting down the hill into town with our 2001 Adventurer towing our 2004 Jeep Wrangler.

The way back up the hill was an exciting trip. We decided to not make the motorhome work that hard so we drove the Jeep and motorhome up separately. For the record there are several pull offs along the way and at the top of the hill to hook up on unhook.

It was a cool foggy morning when we left. The higher we climbed the foggier it got. About half way up the hill a bicycle went screaming by the motorhome heading into town. A couple minutes later another one went by. Shortly there after they were appearing by the dozens out of the fog just a few feet in front of the motorhome heading down the hill.

We just happened to leave when one of the local tour companies was starting their daily ride down the mountain and into town. Apparently they do it rain or shine and whether it's foggy or not.
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Old 02-16-2015, 03:39 PM   #13
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dont ride your brakes to keep your speed down, be very aggressive with them. Slow it down fast and them get off of them.

I started hitting mine when the rpms hit 3500 to 4K and I was in low. I would break until I was doing at most 10mph. I never went down in 2nd or drive.
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Old 02-16-2015, 03:47 PM   #14
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When you do the hard application of brakes be sure to warn your passengers!
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