Hi All, We are planning an out west trip this year which will include extensive mountain driving. Yellowstone, Tetons, Glacier are just a few of our planned visits. My main concern is weather to manually shift the Allison or let her do as she wishes. I do know to use the exhaust break, go down the mountain no faster than I went up and to pump the breaks as opposed to riding them to help keep them cool. Most of my research indicates to let the transmission decide. So all you experienced mountaineers I would love to hear your input. On a side note, any suggestions or must sees would be appreciated. Lastly, should I bring a dehumidifier? I was in NC over the summer and had a tremendous amount of moisture in the coach and do not want a repeat of that. thank you in advance!

You will slow a bit on steep grades but will make it to the top(the computer does a good job)exhaust brake will control the decent. I have a dehumidifier in our closet and keep a humidity meter on the counter .I have had a Winnebago 42qd and now an Entegra 45b (with 600hp) both slow down on steep grades,most people on the forums over worry(arm chair quarterback) drive and enjoy.

We pulled a 5th wheel up there and I don't recall any serious mountain roads. The only hard road was The Road to the Sun in Glacier but big RV's were discouraged to go up there and were prohibited past a certain point - we just drove our truck up there. When I'm doing some serious grades I shift to manual and use the exhaust brake.

Mountain Directory West is a helpful reference.

I think with exhaust brake if you have to touch brake pedal on the hill it is driving error. Even without exhaust brake you should downshift to not need brakes more often than 3 every minutes.

Transmission will do most of the work, but if you are going up an incline and it is such the transmission starts "hunting",shifting up then down just manually put it in a lower gear a pick a reasonable speed for the gear and go up the hill. If you have an exhaust break start down the hill at the speed where it will maintain the speed with out increasing or without using the service brakes. You do not want to allow going downhill too fast. With a little experience this will all become second nature.

Mountain driving | Good Sam Community

wolfe10
Explorer
Jul 22, 2016
Correct.

Exhaust brakes are either ON or OFF.

Engine compression brakes are often offered with a HIGH (all 6 cylinders) and LOW (3 cylinders)doing the "braking".
Mile_High
Explorer
Jul 22, 2016
The exhaust brake on that tour will do you well! You should have the hi/lo on that (mine is only one setting).

Once that Allison reaches a certain speed over the gear you are trying to downshift into, it won't do anything. At that point you have to brake down slow enough for it to downshift. Kind of a pain. Better bet is when you crown the hill, pick a conservative gear while you are going slow - you can always upshift.

ON EDIT - I have been "privately" corrected that there is no such thing as a hi-lo exhaust brake, so pardon my ignorance - its whatever you push that says Engine Brake and has a Hi-Lo on it. Comes on every 450 Freightliner I've ever driven. :R
RayChez
Explorer
Jul 22, 2016
You shouldn't have any problems. Use your Pac-brake going down all grades and if it is still picking up speed, just tap on the brake pedal for a couple of seconds. Do not ride the brakes going down hill.

I just got back from Yosemite, Ca and it was a piece of cake. Been to Yellowstone many times and I do not remember any steep grades, unless you come down through Cody, Wy. I believe it is highway 14 which is very steep according to posts I have read. I usually come down from the north coming from Montana, or the west coming from California and it is not bad at all.
tinkerer
Explorer
Jul 22, 2016
It depends on traffic condition also. Generally a loaded semi is a little slower than my coach, so if there is a quite a bit of traffic I don't like changing lanes often so there are times I tuck in behind a truck and shift manually keeping the rpms up so it doesn't begin to overheat from low rpms. This might not be true for all coaches though.
lenny-shawna
Explorer
Jul 22, 2016
Thank you everybody, I really appreciate all the valuable insight you shared with us.
Kayteg1
Explorer II
Jul 21, 2016
Bikeboy57 wrote:
There have been some good comments.

Let me add two things.

One, I find that if I take the mountain curves 5 or 10 mph less than the posted sign that my co pilot is much happier.

Two, keep an eye on your engine temp when climbing long grades. If you think it is starting to rise much above normal, then force the transmission into the next lowest gear. The higher RPM will increase the fan speed and pump more air through the engine, both help with cooling.

Not only more air, but going slower, you will use less HP / minute, meaning the engine will generate less heat.
Not too many vehicles have cooling system design to drive with gas pedal on the floor for long minutes. Some diesels can do it but this is one of the common misconceptions.
JoeH
Explorer III
Jul 21, 2016
Since you have a Freightliner, set up your light bar display to show engine temp and tranny temp so you can monitor them. When climbing hills out there, I found that I had to manually downshift to keep the engine coolant temp from getting to hot. That was only a couple pretty severe roads most of the time the engine/tranny knew where to be.

We spent a few months out there last summer and really liked the national parks in Utah. From there we headed up to Yellowstone and the Grand Tetons.
Bikeboy57
Explorer
Jul 21, 2016
There have been some good comments.

Let me add two things.

One, I find that if I take the mountain curves 5 or 10 mph less than the posted sign that my co pilot is much happier.

Two, keep an eye on your engine temp when climbing long grades. If you think it is starting to rise much above normal, then force the transmission into the next lowest gear. The higher RPM will increase the fan speed and pump more air through the engine, both help with cooling.
RedRocket204
Explorer
Jul 21, 2016
Only one person slightly eluded to this so wanted to bring it up...

Sounds like you possibly have no experience driving the mountains out west and that is fine and is good you are asking. There has been good information mentioned in the responses but also, please make sure you are being considerate by using right lanes and turnouts when you are the slower vehicle on the road. Many mountainous roads have limited amounts of lanes and it is considered a good driving habit to be aware of others on the road, being considerate in the process using right lanes/turnouts.

Thanks and enjoy your trip!
eubank
Explorer
Jul 21, 2016
You know, mountain driving is more than just uphill and downhill. It means curves, lots of them, requiring you to slow down even more than during straighter stretches. Often enough, it's a hairpin that will require you to be at less than half of your speed in straight stretches.

Under those common circumstances here in the west, I always downshift and keep it slow. Remember this: If you're going at a good speed now, you won't be for long because you'll be too fast for the curve ahead of you.

Lynn