mountain driving

[ga traveler]

I always told my customers 4000 to 4400 rpm climbing a mountain. This came from the man who designed the V10. I talked to him at the December dealer show every year in Louisville. Remember the water pump has to move water through the radiator to cool it. If you are driving with the engine at low rpms, the water pump is moving water slowly. At 4000 to 4400 rpm's you are at a good speed for cooling and power.

[edge68474]

Good response. Hand clap.

[hohenwald48]

Originally Posted by Waiter21

I have the older 4R100 (Ford) I usually allow the trans to downshift, then will manually downshift so the transmission can't upshift until we reach the top of the summit, then I'll allow manually move to a higher gear..

The downshift / upshift probably bothers me more than it does the transmission. On long steep climbs, I'll hold 4000 rpm and whatever speed the gear gives me.. In second gear its around 45 mph. In 1st gear its around 25 mph.. Keep the rpms up. rpms is power..

I do the same thing on my 5 speed F-53. But be careful. I went up a mountain in AZ and got to the top. Nudged the shifter back to D and headed down the other side. There was a good bit of traffic too. I tapped the brake to force the transmission to down shift and hold my speed down on the downhill side and it didn't downshift. Speed continued to rise. Tapped the brake again, no down shift and speed keeps rising. Finally I got heavy on the brakes to get the speed down and was really starting to worry how I was going to make it all the way down with no downshift and without burning up the brakes. Looked at shift indicator and I had missed D and was coasting in N coming down a steep hill. So be careful when shifting backup to D.

[uncbearfan]

Originally Posted by hohenwald48

I do the same thing on my 5 speed F-53. But be careful. I went up a mountain in AZ and got to the top. Nudged the shifter back to D and headed down the other side. There was a good bit of traffic too. I tapped the brake to force the transmission to down shift and hold my speed down on the downhill side and it didn't downshift. Speed continued to rise. Tapped the brake again, no down shift and speed keeps rising. Finally I got heavy on the brakes to get the speed down and was really starting to worry how I was going to make it all the way down with no downshift and without burning up the brakes. Looked at shift indicator and I had missed D and was coasting in N coming down a steep hill. So be careful when shifting backup to D.

That's a scary feeling. Another reason I feel it's good to start down the hill 1 gear lower than you pulled it. Verify you're in the right gear before descent.

[firedoc]

Originally Posted by hohenwald48

I do the same thing on my 5 speed F-53. But be careful. I went up a mountain in AZ and got to the top. Nudged the shifter back to D and headed down the other side. There was a good bit of traffic too. I tapped the brake to force the transmission to down shift and hold my speed down on the downhill side and it didn't downshift. Speed continued to rise. Tapped the brake again, no down shift and speed keeps rising. Finally I got heavy on the brakes to get the speed down and was really starting to worry how I was going to make it all the way down with no downshift and without burning up the brakes. Looked at shift indicator and I had missed D and was coasting in N coming down a steep hill. So be careful when shifting backup to D.

Why would you shift to D to come down the hill rather than come down in same gear you went up. Of course it gained speed coming down, even if not in neutral.

[A32Deuce]

They generally tell you to go down in the same gear you went up.

[96 Softail]

Originally Posted by lynnmor

You need to understand the chart showing your horsepower. You will have the most power to climb the mountain at the peak horsepower and that is always at a higher RPM than peak torque. Of course I don't expect agreement from the torque fan crowd.

Now the idea of going down the mountain in the same gear you went up is somewhat out of date. With the power of recent engines, the gear required might be quite different.

I understand power charts perfectly.
Peak hp to climb a mountain for a gas engine.
Peak torque to climb a mountain for a diesel engine.
Why is this? It’s because a gas engine developes more hp than torque. And a diesel engine developes more torque than hp.

[WeatherTodd]

if this doesnt scare you into owning an Allison equipped motorhome... I dont know what will...lol

[edge68474]

I used to haul our equipment for the construction outfit I worked for, just to give you a little background. This equipment ranged in weight from say 15000 lbs., to 120,000 lbs.
So I am going to say I know about gears and shifting up and down to keep the rig under control, and, keep the engine COOL. And to keep it cool, you need to be in the higher rpm's for your engine, not lower, and especially if you drive an older rig. Things just don't work as well as when new and even if it was new, would you want to keep overheating it. Not Good.
Put it in a gear while climbing so that the motor isn't struggling and you can back off the throttle some. Enjoy the ride going up. Downhill, shift to a gear that will hold you back without it revving too high, and hardly any throttle if any. All of this is going to vary some depending on your rig. You will learn and get to know your rig soon. Don't let it get out of control.
Keep it COOL, keep it under CONTROL. Don't PANIC.
Oh, out of courtesy , if you are going slow, say 45 or 50 or less in a 60 or above zone, please put your 4 way flashers on so those coming up on you know that you are going slow. It's just a nice thing to do.


PS. If you have a Jake or Retarder in your rig, I'm jealous, LOL.

[YooperVer]

Originally Posted by 96 Softail

I understand power charts perfectly.
Peak hp to climb a mountain for a gas engine.
Peak torque to climb a mountain for a diesel engine.
Why is this? It’s because a gas engine developes more hp than torque. And a diesel engine developes more torque than hp.

If one says things like "...develops more torque than horsepower" they do not understand power charts perfectly, that is for certain. No disrespect intended, but would recommend you review definition of physics properties of Force and Power and rethink the problem.

[hohenwald48]

Originally Posted by firedoc

Why would you shift to D to come down the hill rather than come down in same gear you went up. Of course it gained speed coming down, even if not in neutral.

You do know that when you crest a mountain pass out west you're going aboout 10MPH as you come over the top. You do know the Ford transmission is designed to downshift when you tap the brake only if the lever is in D. Why would I come over the top of a pass and then leave the transmission in 1st or 2nd gear and not build up at least a minimum amount of speed for the decent?

The goal when climbing is to maintain 3500-4000 RPM. The goal when descending is to not exceed a safe speed and to maintain a speed that is reasonable while still being safe. Why would I want to go down in 1st or 2nd gear going at the same 10MPH I came up?

I think the go down in the same gear you go up info was spread around by someone who thinks the Smokey Mountains are mountains.

[uncbearfan]

Originally Posted by hohenwald48

You do know that when you crest a mountain pass out west you're going aboout 10MPH as you come over the top. You do know the Ford transmission is designed to downshift when you tap the brake only if the lever is in D. Why would I come over the top of a pass and then leave the transmission in 1st or 2nd gear and not build up at least a minimum amount of speed for the decent?

The goal when climbing is to maintain 3500-4000 RPM. The goal when descending is to not exceed a safe speed and to maintain a speed that is reasonable while still being safe. Why would I want to go down at the same 10MPH I came up?

Because you can ALWAYS shift to a higher gear. However if you start the decent at too high of a gear and you're pegged at 4500 rpm you may not be physically able to downshift without wearing your brakes out and then you're in trouble. Depends on your rig but why risk it? Start low and move up if you're comfortable, you're in control that way.

[hohenwald48]

Originally Posted by uncbearfan

Because you can ALWAYS shift to a higher gear. However if you start the decent at too high of a gear and you're pegged at 4500 rpm you may not be physically able to downshift without wearing your brakes out and then you're in trouble. Depends on your rig but why risk it? Start low and move up if you're comfortable, you're in control that way.

When I come over the top at 10MPH in 2nd I'm comfortable with D heading down. And not too uncomfortable with N. I've been driving motorhomes all over the country for 20 years. I think I have a handle on what gear to use.

Again, you do know the Ford transmission will downshift with a simple tap on the brakes don't you. You don't have to ride the brakes to get it to downshift.

All I was doing was relating what I thought was a slightly funny story. I wasn't looking for driving instructions or suggestions.

If some folks feel unsafe descending at more than 10-20MPH then they should stay in 2nd gear. I'm comfortable with a little more speed than that. I'd go up at 60MPH if I could.

[uncbearfan]

Originally Posted by hohenwald48

When I come over the top at 10MPH in 2nd I'm comfortable with D heading down. And not too uncomfortable with N. I've been driving motorhomes all over the country for 20 years. I think I have a handle on what gear to use.

Again, you do know the Ford transmission will downshift with a simple tap on the brakes don't you. You don't have to ride the brakes to get it to downshift.

All I was doing was relating what I thought was a slightly funny story. I wasn't looking for driving instructions or suggestions.

Lol. I get that, I know my rig too and what it can handle. Was just offering arguments for the OP who had questions, and advice for anyone with a new rig. Always start slow until you know what your rig can do.

Let me know when youre passing through Colorado and we'll race down the mountain. [emoji15]