How steep a grade...

[Versatile]

Originally Posted by cowlitzcoach

I drove harvest truck for several seasons going from the processing plant in western WA and the corn/carrot fields in the Columbia basin in central WA. It required going back and forth across White Pass on US12. The top of White Pass is 4000' and the bottom on the western side is less than 1000'. A 3000' drop in seven miles can be a bit of challenge when you throw in the fact it is a two lane highway with lots of twists and turns.

One night heading back to the plant with a full load of fresh corn on board, 105,500 lbs. give or take 1,000 lbs. I went over the crest of the pass and went to hit the jakes for the first curve on the downhill side. Needless to say I went into full pucker factor when the jake did not engage.

Going down a steep hill with a lot of curves in a gear or two higher than what you would be in if you didn't have a jake brake is more than a little bit disconcerting.

Fortunately the road levels out in places which allowed me to start dropping gears before I got to the next steep portion.

I would never have gone over the crest in such a high gear if I had any inclination that the jake was non-op. It had been working on the trip east and so far on the trip west. Leave it to Murphy to apply the law to the steepest down grade of the whole trip.

So instead of a gear that would keep me in the 35-40 MPH range I was a couple of gears lower in a gear that would keep me in the 25-30 MPH range.

Glad you made. When it starts happening; then it happens real quick but seems to last forever.

[cadillackid]

I dont use WAZE for the GPS piece, I use it for the traffic piece... I have copilot truck for my navigations.. mnainly just because a truck GPS will never tell you to U-turn whereas the consumer one will... my DEV bus is 10'8". and the RedByrd is under 10 so I am pretty good with height except perhaps some of the craziness in new england and such... the RedByrd is only a foot and a half longer than a dualie crew cab pickup... so most corners i can do well with
-Christopher

[Brewerbob]

Originally Posted by jctrembly

Would you believe some of these fleet's today still spec trucks without an engine brake of any kind. All to save a few pennies.

If they are the same as my bus, absolutely!!! Mine doesn't go downhill fast enough.

[EastCoastCB]

Originally Posted by Brewerbob

If they are the same as my bus, absolutely!!! Mine doesn't go downhill fast enough.

You and me both got 4.44's and a 643 trans. Good for the steep stuff, IMO.

[Iceni John]

Originally Posted by jctrembly

I guarantee you did! I was in an old loaner truck and a wire came loose from the Jake. I wasnt close to your situation but it really made me think about how to handle that situation should it have became a problem. I'm glad you were able to stay safe.


Sent from my Nexus 5X using Tapatalk

After I completely overhauled my Jakes last year I realized that there are too many potential points of failure that could possibly prevent them working if something were to go wrong. To help counter that, I now have a new emergency toggle switch with a red flip-up cover next to me that sends 12V directly to both banks' solenoids, i.e. it makes the Jakes work regardless. With this new switch I can force them on, even if under load or at idle (which normally can never happen). It could also be useful for diagnosing problems. Essentially this new switch bypasses the ECM's own internal brake control, the Jake relay and the normal Hi/Lo Jake switch, so even if the ECM or relay failed I could still use the Jakes.

Always have a Plan B! Actually I never go down hills faster than if I did not have Jakes at all, and I use them to keep my brakes as cool as possible. The last time I came down Cajon Pass I didn't touch my brakes at all, all the way down. Plus they do sound cool!

John

[jctrembly]

I like the bypass switch. That's a good idea even if just to use it for Diagnostic.

Sent from my Nexus 5X using Tapatalk

[EastCoastCB]

Originally Posted by Iceni John

After I completely overhauled my Jakes last year I realized that there are too many potential points of failure that could possibly prevent them working if something were to go wrong. To help counter that, I now have a new emergency toggle switch with a red flip-up cover next to me that sends 12V directly to both banks' solenoids, i.e. it makes the Jakes work regardless. With this new switch I can force them on, even if under load or at idle (which normally can never happen). It could also be useful for diagnosing problems. Essentially this new switch bypasses the ECM's own internal brake control, the Jake relay and the normal Hi/Lo Jake switch, so even if the ECM or relay failed I could still use the Jakes.

Always have a Plan B! Actually I never go down hills faster than if I did not have Jakes at all, and I use them to keep my brakes as cool as possible. The last time I came down Cajon Pass I didn't touch my brakes at all, all the way down. Plus they do sound cool!

John

Jakes are COOL, no doubt. But for us "owner/operators" they're pretty expensive and complex. Why I like the Retarder option so much. Seems PERFECT for taking a skoolie across the Rockies.

[Brewerbob]

Originally Posted by EastCoastCB

You and me both got 4.44's and a 643 trans. Good for the steep stuff, IMO.

Steep downhill maybe. Sucks for going uphill.

[EastCoastCB]

Originally Posted by Brewerbob

Steep downhill maybe. Sucks for going uphill.

Meh, my 466/643/4.44 does great in the steep grades.

[Brewerbob]

Originally Posted by EastCoastCB

Meh, my 466/643/4.44 does great in the steep grades.

I have a little bit more bus behind my 643. Well, in front of actually but you know what I mean.

[EastCoastCB]

Originally Posted by Brewerbob

I have a little bit more bus behind my 643. Well, in front of actually but you know what I mean.

How so?
I've got forty feet of bus, man. 18k lbs completely gutted.

[Iceni John]

EastCoast CB,

If it's a Telma electro-magnetic retarder you're good for long grades, as long as your alternator can reliably supply enough amps for it. All the heat produced just blows harmlessly out under the bus. If it's a transmission retarder, you can easily overheat (or worse) your transmission coming down a long grade, even with a large transmission fluid cooler. At the very least, have a good transmission temperature gauge if you also have a transmission retarder, and watch it like a hawk when going down long grades. For the really long grades, such as I-80 westbound from Reno NV after Donner Summit where there is 70 miles (yes, 70 miles!) of 4%, 5% and 6% downgrades until just before Rocklin CA, only Telmas and Jakes are effective. What works back east may not always be much good out west!

Be careful!

John

[EastCoastCB]

Originally Posted by Iceni John

EastCoast CB,

If it's a Telma electro-magnetic retarder you're good for long grades, as long as your alternator can reliably supply enough amps for it. All the heat produced just blows harmlessly out under the bus. If it's a transmission retarder, you can easily overheat (or worse) your transmission coming down a long grade, even with a large transmission fluid cooler. At the very least, have a good transmission temperature gauge if you also have a transmission retarder, and watch it like a hawk when going down long grades. For the really long grades, such as I-80 westbound from Reno NV after Donner Summit where there is 70 miles (yes, 70 miles!) of 4%, 5% and 6% downgrades until just before Rocklin CA, only Telmas and Jakes are effective. What works back east may not always be much good out west!

Be careful!

John

Well, I'll never be able to afford anything with a REAL jake, so retarders are my only option. Especially since they came in some western buses from the factory.
I live in FL, I've never even used a retarder or personally seen a bus with one.
My forty foot bus did some 6% sustained grades on the trip home and the 643's lockup tc was really GREAT to have. ANY retarder would have made my day a little less stressful. What works "back east" is any bus, with any transmission, with any brakes.
I've known PLENTY of folks who drive crappy eastern buses right thought the Rockies like they're not even there, but being from FL I'd sure feel better having ANY sort of auxiliary braking if/when I do decide to try my luck at it.

[Brewerbob]

Originally Posted by EastCoastCB

How so?
I've got forty feet of bus, man. 18k lbs completely gutted.

Thought that was the shorty. Uphill I can do 40 and that's it. My title said just under 17,500.

[Brewerbob]

Originally Posted by Iceni John

EastCoast CB,

If it's a Telma electro-magnetic retarder you're good for long grades, as long as your alternator can reliably supply enough amps for it. All the heat produced just blows harmlessly out under the bus. If it's a transmission retarder, you can easily overheat (or worse) your transmission coming down a long grade, even with a large transmission fluid cooler. At the very least, have a good transmission temperature gauge if you also have a transmission retarder, and watch it like a hawk when going down long grades. For the really long grades, such as I-80 westbound from Reno NV after Donner Summit where there is 70 miles (yes, 70 miles!) of 4%, 5% and 6% downgrades until just before Rocklin CA, only Telmas and Jakes are effective. What works back east may not always be much good out west!

Be careful!

John

I-64, 79, 68, and 70 thru WV to MD was slow as hell going uphill. I watched the trans temp gauge going uphill but not downhill. Flat, up, and whenever I glanced at it, it never moved. It stayed at 155°F. The other bus had the MD3060. Her gauge started where mine was reading. I don't think she ever broke 160~165°F. Whatever the first tick mark is.

I've no idea how those roads compare to yours. It certainly ain't 70 miles straight of it. The signs read 5% & 6% mostly, and one 7%.

[EastCoastCB]

Originally Posted by Brewerbob

Thought that was the shorty. Uphill I can do 40 and that's it. My title said just under 17,500.

My RYO bus is 40' from bumper to bumper. It can do 45 or so up a pretty good grade. My shorty with its little 444 can cruise over BIG hills with the CC set at 65 all day!
Why I want a shorty with a 466 so bad, that thing would be a TANK!

[Brewerbob]

Originally Posted by EastCoastCB

My RYO bus is 40' from bumper to bumper. It can do 45 or so up a pretty good grade. My shorty with its little 444 can cruise over BIG hills with the CC set at 65 all day!
Why I want a shorty with a 466 so bad, that thing would be a TANK!

Cruise on at 55 and left to its own devices, I would drop to 38mph, drop a gear and then chug up it at 40~42 most hills. The last two hours of my trip I was hitting 2500 rpm down hill and managed to stay above 45 most times. I need whatever engine is in the Peter Pan motor coaches I going up I-95. Those suckers are doing 75+ (in a 65 mind you) regardless of hills.

I don't know if the are Vans, Prosts, or MCIs. Just know they are FAST!!

[EastCoastCB]

Yup, I felt a bit of envy every time a coach flew past me on the interstate. Some of em had to be going 80+.

[jctrembly]

The WV in our area use exhaust brake, they have been pretty reliable and avoids the issue that transmission retarders have. With the MD3060 when the exhaust brake activates the Torque converter locks, I doubt that causes much heat.

I drove one of the newer Blue Birds with a 5.9 (last year they sold it) with an auto & exhaust brake. That setup was horrible. Every time you let off the fuel the bus would instantly downshift (engine screaming) and engage the exhaust brake, press on the fuel and it would up instantly upshift. Of the busses that came in that year all specs the same, this was the only one that would do this. It made using the exhaust brake a bit irritating. IE: only on a long grade. No one knows why that's trans is programed differently.

Sent from my Nexus 5X using Tapatalk

[Brewerbob]

Originally Posted by EastCoastCB

Yup, I felt a bit of envy every time a coach flew past me on the interstate. Some of em had to be going 80+.

A bit of envy? A whole lot of envy is more like it. Sometimes they are going too fast for the TDI wagon. They are low to the ground so I prefer them to any other vehicle for drafting but if they are going over 75, I just sit back and wait for the next semi with side skirts to come into view and jump behind them.