Is there already a thread...??

[rjnye79]

Just wondering if there have already been postings on the topic of mountain driving techniques. I'm specifically curious about those, like myself, with pretty straight forward automatic transmissions and hydraulic breaks.

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[turf]

there sure are some threads about mountain driving!

as an owner of an AT545, i've posted my distress after my first trip and a few other trips to the mountains. there are a few other threads about mountain driving too.

generally, its not an issue, unless you have the AT545 transmission. if you have an AT545, go slow. go slower downhill than you do uphill. otherwise, the bus just slips away out of control.

the AT545 does not lock up in any gear. once you crest a hill, there is nothing holding you but your brake. downshifting just shreds the transmission. its similar to putting the bus into neutral and letting it freewheel down a mountain, only the transmission makes all sorts of destructive noises while its still engaged in gear.

[BigDavid]

Now your scaring me.

[EastCoastCB]

Originally Posted by BigDavid

Now your scaring me.

Whats scary is sitting in a 20k lb bus and looking up or down a serious grade.
But I was careful to avoid the 545.
I just bought a shorty with a 545 but in a big bus I would steer clear of them.
I've seen Colorado buses with 545's and driveline retarders- that's a whole different story.

https://www.youtube.com/watch?v=EW5LeTV07Tk

Since the subject is buses and mountains, here's me going over and down a 6% grade that's miles long in TN known as Monteagle-

https://www.youtube.com/watch?v=W5PZvtSvp9s

I've got the 643 in my fullsize, so I wasn't TOO worried. But I'm a FL boy, and those runoff ramps did make me a little uneasy, but at least they were there!
Hear how easy a time my bus is having, though? The engine isn't revving too hard or out of control. That's because it has the locking t/c.

[rjnye79]

Originally Posted by turf

there sure are some threads about mountain driving!

as an owner of an AT545, i've posted my distress after my first trip and a few other trips to the mountains. there are a few other threads about mountain driving too.

generally, its not an issue, unless you have the AT545 transmission. if you have an AT545, go slow. go slower downhill than you do uphill. otherwise, the bus just slips away out of control.

the AT545 does not lock up in any gear. once you crest a hill, there is nothing holding you but your brake. downshifting just shreds the transmission. its similar to putting the bus into neutral and letting it freewheel down a mountain, only the transmission makes all sorts of destructive noises while its still engaged in gear.

We do have the AT545... [emoji53] so, do you just feather the brakes from top of the grade to the bottom? I imagine that just riding the brakes is not necessarily a good thing either...

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[Scooternj]

Originally Posted by rjnye79

We do have the AT545... [emoji53] so, do you just feather the brakes from top of the grade to the bottom? I imagine that just riding the brakes is not necessarily a good thing either...

At least with air, you feather the brakes. Riding them runs the risk of glazing, and brake malfunction.

[EastCoastCB]

Just gotta go slow and take your time. Don't ride the brakes, use them in bursts to keep the speed down as necessary.
You gona be in the eastern mountains or the real mountains out west?

[rjnye79]

Well, we're out West now (Texas, heading up into Colorado) but we don't plan on crossing any major ranges. Just skirting them as much as possible. Avoiding I-70 West from Denver, for example.

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[EastCoastCB]

Originally Posted by rjnye79

Well, we're out West now (Texas, heading up into Colorado) but we don't plan on crossing any major ranges. Just skirting them as much as possible. Avoiding I-70 West from Denver, for example.

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You'll be fine, just take any serious grades really easy.

[BurlKing]

Originally Posted by EastCoastCB

Whats scary is sitting in a 20k lb bus and looking up or down a serious grade.
But I was careful to avoid the 545.
I just bought a shorty with a 545 but in a big bus I would steer clear of them.
I've seen Colorado buses with 545's and driveline retarders- that's a whole different story.

Since the subject is buses and mountains, here's me going over and down a 6% grade that's miles long in TN known as Monteagle-

I've got the 643 in my fullsize, so I wasn't TOO worried. But I'm a FL boy, and those runoff ramps did make me a little uneasy, but at least they were there!
Hear how easy a time my bus is having, though? The engine isn't revving too hard or out of control. That's because it has the locking t/c.

great driving eastcoastcb! haha i hear you about runoff ramps, here in mn its pretty much all flat and i've rarely seen runoff ramps and when i do im like oh man what did i get myself into now....

[rjnye79]

Originally Posted by EastCoastCB

You'll be fine, just take any serious grades really easy.

Thanks, that makes me feel a lot better... and your advice is helpful too. ;D

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[turf]

my break in to the AT545 was coming back down I-70 towards Denver after a weekend of camping in the high country.

wall to wall traffic, steep grade, real curvy, and everyone is doing 70mph. i thought i destroyed the trans on the way down. i thought i'd tip the bus, i was just flat out of control. it was a white knuckle ride with a brown spot in my pants.

if you feather the brakes, they'll heat up. once coming out of rocky mountain national park, i caught the rear brake on fire. brakes dont work very well while they burn. at the bottom, i pulled over for an hour or so to let everything cool down.

now with some practice, i'm much more confident than some of my early trips. the easy rule for me now, is don't go any faster than i did up the grade. in the bus on grades, uphill is slow (20-45mph). on the way down, at 45, i gently slow the bus down to 35, and let gravity accelerate back me up to my 45. and repeat.

the transmission has a very light "lock up" connection. on the descent, it seems to help to kinda give the motor enough throttle that the trans stays "locked" even though its not going to hold you.

so coming down is a combination of braking and throttle (to avoid that freewheel). and staying under a safe speed. it takes some practice.

i wouldn't avoid the mountains because of the hills. but i also wouldn't recommend learning about the descent process on a busy highway like I-70. find some uncrowded grade, early in the morning before any traffic rush, toss on those flashers and see what happens.

slow and boring is the right way. good luck!

[turf]

one more thing i'll add.

i tow with my bus. i work the bus hard. and the transmission has taken care of me , when i haven't taken care of it.

descending a hill is the obvious issue with a bus or any heavy vehicle. less obvious is the ascent and the heat build up you get in the transmission.

i believe i cracked my exhaust manifold from pushing the bus to hard up a hill. when you climb a hill and slow down, the motor doesnt slow down, its still pushing the trans the same or more than it did on flat land.

the slow speed is because the transmission and motor are connection through a liquid torque converter. the speed you aren't getting is dissipated as heat in the transmission.

i climbed monarch pass, and by the top, the truck was reduced to a crawl (i could've walked faster). all that heat goes somewhere... and i cracked my exhaust manifold.

i'm lucky if that was all the damage done. im replacing that manifold now, and am adding some temp gauges to let me know about the transmission and exhaust temps.

i also added a transmission cooler after that hill climb, and the truck loves it. its made me able to keep up in traffic on those hills, instead of being a turtle on the side of the road. now i can pass jeeps if they're towing. im not the slowest on the road anymore.

still, chill out on the hills, put on the flashers and enjoy the ride.

[cadillackid]

ive run the Monteagle in my 545... keeping the speed below 50 on the downhill allows you to downshift your 545 into 3rd gear... it has decent holding power in 3rd gear.. below 30-35 you can shuift to 2nd and the 545 holds very well in that gear...

in 4th gear the 545 free-wheels for the most-part..

I have 2 shorties.. one is a GVWR of 27500 and the 17500.. ive run the 27500 through the appalachains, smokies, and adirondacks. but not the rockies..

there are folks here running 545's through the rockies..

pay attention to what you are doing.. the stab-N-Slide method works good for Air-brakes...

drop your bus to 3rd gear (in a 545).. and if it goes fast enough to shift back to 4th on its own.. stab the brakes to drop your speed 5-7 MPH then release... if you really feel uncomfomfortable then at the top of a grade drop your speed to where you can hold in 2nd, turn on the flashers and stab N release to keep the trans in second..

dont worry about the rest of the traffic... go only as fast as YOU are comfortable driving your bus..

MT-643's and MD3060;'s are definitely much better than 545s in the nountains.. but plenty of 545s have run em and been fine..

ECCB - you found a shorty????
-Christopher

[family wagon]

Originally Posted by turf

if you feather the brakes, they'll heat up. once coming out of rocky mountain national park, i caught the rear brake on fire. brakes dont work very well while they burn. at the bottom, i pulled over for an hour or so to let everything cool down.

I concur: IMHO "stab braking" is better than "feathering." To me the latter means basically lightly riding the brakes continuously. In the stab braking style, the truck is allowed to reach whatever limit you've deemed safe and then brakes are applied firmly, as if you really meant to come to a stop, so that the truck's speed drops 5-10 MPH fairly quickly. Then stay off the brake entirely and let the truck build speed up to your limit point and repeat.

I like that style for two reasons. First is that the armchair thermodynamicist thinks it makes sense.. The bus has a certain amount of potential energy because it's a mass at some elevation and it's headed down hill. That potential energy has to be turned into heat energy by the brakes, and it has to be transferred out of the brake rotor/drum into the surrounding air. Heat transfer is more efficient when there's a greater temperature difference. It seems to make sense that stab braking will cause the drum temperature to spike quickly to a higher temperature, and because of the higher temperature (relative to brake feathering) the heat energy will transfer into the air more quickly. That leaves the brake system relatively cooler at the start of the next braking cycle. Then again, I'm not a professional in these things, so maybe this is all crazy-talk.

On to the second reason: I believe that an attentive driver will get a feel for how the truck responds to a brake stab. If the brakes begin to fade, the driver will notice that they're just not working as well as the used to and can use whatever braking ability remains to bring the vehicle to a stop quickly and wait for things to cool. On the other hand, if a driver is only feathering lightly, he won't detect the reduction in braking performance until there's already nothing left. At that point it's just too late.

[cadillackid]

the reason I believe in stab braking is that when you stab you heat the entire inner lining of the brake up as well as some of the mechanical parts very quickly.. when you release the rest of the drum is relatively cool and the heat then travels toward the outer cool part of the drum and the inner part cools fairly quickly makign the brake ready again..

also in the stab method you have a much higher chance of getting a full mating of pad material against drum. reducing the chances for hot spots.. hot spots on the pad material can glaze it and make it ineffective.. if there are deviations in the pad and drum from eschj other, feathering will heat only a portion of the pad material up hot enough to glaze.. as opposed to getting a good full-service area mating..

*IF* you are TRULY in trouble then you want to run the bus as fast as you can and still control it.. as you then have head-wind energy to help slow you down as well as air over the brake drums.. but this is ONLY a mneasure if you are truly in trouble..

and all of family-wagons points apply as well...
-Christopher

[turf]

yep, what they say!!!

to add on top of it, the stab braking doesnt count for sh*t if your going faster than say 50 mph. its the same as feathering, because you'll speed back up that 10 mph in just a couple seconds on a steep down hill.

keeping your speed under control is mostly a matter of not letting it get up there.

for the most part, follow the truck speed signs, there is a line of slow guys in the right hand lane. sit back and enjoy the ride.

[turf]

lol, i just had an evil thought.

maybe at Colorado #3, we can have some downhill races

[family wagon]

I guess I wouldn't be any fun at downhill racing... My bus has the Allison B300R transmission with built-in retarder ("R" suffix). A couple years ago I drove it down White Bird Hill, which is known to locals on the western edge of Idaho as a pretty severe grade. Idaho highway 95 drops from 4400 feet to 1600 feet over the course of about 7 miles with a maximum grade of 7%. From what I can tell, it's 7000 feet lower elevation overall but a comparable grade to what one experienceson the famous I-70 in Colorado..

Anyway, paranoid as I was after the admonition received from my parents and grandparents, I put the retarder at is maximum setting and crossed my fingers. There was no need to touch the service brakes at all; I just moved the retarder control up and down. Kept an eye on the transmission oil temperature gauge and was surprised how little it climbed -- they must have put a really good tranny cooler on this bus!

[EastCoastCB]

Originally Posted by cadillackid

ive run the Monteagle in my 545... keeping the speed below 50 on the downhill allows you to downshift your 545 into 3rd gear... it has decent holding power in 3rd gear.. below 30-35 you can shuift to 2nd and the 545 holds very well in that gear...

in 4th gear the 545 free-wheels for the most-part..

I have 2 shorties.. one is a GVWR of 27500 and the 17500.. ive run the 27500 through the appalachains, smokies, and adirondacks. but not the rockies..

there are folks here running 545's through the rockies..

pay attention to what you are doing.. the stab-N-Slide method works good for Air-brakes...

drop your bus to 3rd gear (in a 545).. and if it goes fast enough to shift back to 4th on its own.. stab the brakes to drop your speed 5-7 MPH then release... if you really feel uncomfomfortable then at the top of a grade drop your speed to where you can hold in 2nd, turn on the flashers and stab N release to keep the trans in second..

dont worry about the rest of the traffic... go only as fast as YOU are comfortable driving your bus..

MT-643's and MD3060;'s are definitely much better than 545s in the nountains.. but plenty of 545s have run em and been fine..

ECCB - you found a shorty????
-Christopher

http://www.publicsurplus.com/sms/auc...ew?auc=1770873
I bought this guy last night. 1998 6 window Amtran with WC lift. Hydraulic brakes. 4.10 rear end is nice, and nearly new tires. Not a bad deal at all at 1625!
YOU convinced me the 444/545 would be ok. I figure for what I'm using it for it will probably be overkill and last forever anyhow. Yep. Its all YOUR fault my addiction has gotten worse!!