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Teton Pass
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Karl, hope you guys are enjoying your trip West,last saw you in OKC. We’re in Council Bluffs heading to Montana, Idaho,Utah and Colorado. Don’t overthink or worry about the upcomming downgrade. Rule of thumb about whatever gear it downshifts to going up is your gear going down. Jake on high or retarder in middle to start, can increase,. watch trans temp if you have a retarder. It’s not as scary as it sounds. Relax and enjoy the view on th way down at between 40-50 mph. Geo.
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Karl, application of the retarder often triggers a downshift so the retarder will retard better. Like a Jake it is more effective at higher revs. This is the default programing of the Allison. I believe the auto-downshift can be cancelled by a programming flash. Since I prefer to downshift it myself, I’m going to look into it. Until then, at the top of a steep grade I slow to the speed I want to decend at, downshift manually, and then apply the retarder. Still I sometimes get an unwanted downshift, that brings my engine RPM higher than I want. At that point I usually shut off the retarder and let the bus upshift and then re-apply the retarder. That process often gets repeated a number of times on a long downslope.
p.s.: I run 6% and 7% grades while towing a Jeep pretty often and I try to keep the bus at around 45mph on a divided multi-lane highway because I feel I can safely stop in a reasonable distance with just the service brakes if necessary. I assume you will encounter 10% downgrades only on a two lane highway. My preference would be to stay at 35mph or under in those conditions, and even less if it’s twisty. As others have said, do not let other traffic on the road affect you. You set your comfort zone and then stay within it.
This is the steepest I’ve yet encountered:
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Jon,
“Even if you are no paying attention the computer is going to limit the temp anyway.”
How does it do this?
Having occasionally driven charter coaches with retarders, I’ve often wondered about this myself. Does it shut off the retarder? That would be scary.
But they sure are nice. I once came up the WV twistpike and hardly used the service brakes.
Ted
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Thx Geo. Disconnect or no? I’m pulling a Dodge 1500.
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Thx Geo. Disconnect or no? I’m pulling a Dodge 1500.
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Karl, No……We pull a 4dr Dakota. I also Tow a 32′ stacker (20K) when I’m racing with no problems in the mountains. Actually the trailer can help….I set the brake controller at its most sensitive setting and just touching the service brakes on the bus activates the trailer brakes and pulls you back a little. Your bus doesn’t even know that Ram 1500 is back there. Geo.
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Current model transmissions have an upper limit of 300 degrees at which point the transmission control module will limit the retarder effectiveness as necessary to prevent the temperature from exceeding that value.
Karl, No need to worry about the toad. You know our Hummer and we have no problems with downhill grades even with that attached as long as we control the gears and speeds.
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We have a retarder and so far in the mountains of Kentucky, Virginia, Tennesse, Georgia, and Wisconsin it has worked fine for us. I have yet to see an increase in trans temp …. presuming the Liberty “Oil Temp” gauge on the dash is the trans temp which I’ve been told.
I would also like a Jake brake because I think they sound better when applied. I’m also considering swapping out our “Train Whistle” for a “Train Horn” which I think sounds better than a “Train Whistle”.
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I don’t have a Jake or retarder and have never had a problem in the mountians. I just go down in the same gear I went up. If I need to use the brakes to keep myself at my target speed then I drop another gear. The biggest key for me is to focus on my target speed, keep my eyes down the road for trouble. It’s very satisfying to me to make it down a hill without touching the brakes at all (while staying in my target speed of course).
(PS – I have a 6 speed manual so I have no I idea if what I do would apply to a slush box – maybe that’s why you gals/guys need Jakes and retarders:) Safe travels!
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Ah Dick, I remember well not too long ago the angst and questions about buying your first Prevost. Look how far you’ve come….trying to decide between a train whistle or horn. Geo.
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Geo: Its a really important decision to make, and most of these new folks don’t realize it yet because they are still drinking the information from a fire hose. That one decision sets the tone for the entire Prevost experience.
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Dick, you can have ours. You R&R and make sure we have no air leaks and patch the hole in the floor. Geo.
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So, it went perfectly fine, thanks to all the help. I have done 8% grades before and wouldn’t have been concerned about this one except for all of the hype on the Wyoming DOT website. It was really a non event. Mostly second gear, sometimes third, with the retarder on the fourth portion and tranny temp never went over 212. Once I pulled over to let traffic by but the second line had to suffer with 25 mph downhill. Several passed mine in no passng areas, even around the curve. Their problem, not mine.
The only concern i had was the sign with flashing lights that said I was over 60,000 pounds. I guess I should reweigh the bus, but my paper says 53,000. My water was almost empty and black tank was totally empty, Fuel at 3/4. Yes the truck was on there, but I think it’s only 4,000.
Anyway, thanks again!
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Good job Karl or Natalie.
Now when someone new asks the question you can help them with the confidence of knowing you did that.
Don’t believe the scale.
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