Author Topic: 4104/4106 Question - mountains  (Read 15209 times)

Offline RnMAdventures

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4104/4106 Question - mountains
« on: February 12, 2011, 01:07:46 AM »
A few years ago I had a 58 4104. I didn't do the traveling I would have liked to in it. I am in the market for another bus and I have been thinking seriously about a 4104, 4106, or a MC5A. However, I never really knew how well the 4104 would handle the Colorado mountains with a spicer 4 speed?

How about a 4106 with an Alison automatic?

Any feedback is appreciated.

Mike
Mike & Rosemarie
1964 PD4106-2626
DD8v71 & Allison v730

Offline 06 Bill

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Re: 4104/4106 Question - mountains
« Reply #1 on: February 12, 2011, 03:18:35 AM »
Mike     We have a 4106 with the V-730 auto & have been all over the western Mtns. Temp rise on long
pulls used to be a prob. until the new radiator, now never attempt's to heat up. We also pull a full size
chevy impala while traveling.  06 Bill 4106 2741

Offline Barn Owl

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Re: 4104/4106 Question - mountains
« Reply #2 on: February 12, 2011, 05:59:37 AM »
I took a fully loaded 4106 with a V730 through the Rockies without a problem and I didn't stick to the beaten path either. Many 10k to 12k passes and long steep grades. The only thing I wished I had was the 6v92 turbo. High altitudes gives the 8v71 lots of smoke and reduced power. My bus has an over-sized radiator (seven core vs four) and the larger cooling fan (eight blade vs six). After seeing some transmission temps that were on the high side while there I bought a Hayden 1290 off of Ebay this winter to supplement the oil/water cooler, and expect to have it installed before I head out this summer. I believe that of the three buses you have listed, the 4106 w/ the v730 is the easiest one to modify for the mountains. That's one of the reasons I have one, it's the only bus that I could reasonably get to my house..... which is in the mountains.
L. Christley - W3EYE Amateur Extra
Blue Ridge Mountains, S.W. Virginia
It’s the education gained, and the ability to apply, and share, what we learn.
Have fun, be great, that way you have Great Fun!

Offline TomC

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Re: 4104/4106 Question - mountains
« Reply #3 on: February 12, 2011, 06:31:57 AM »
Personally-I would stick with a 4106 or MC5 with automatic, with a turbo engine.  You'll be amazed (just like I was when I turbo'd my 8V-71) at the difference in performance-especially in the big hills we have out west that can be over 11,000ft.  On a bus, the only manual I would consider would be at least a 7spd with 10spd being preferred.  Good Luck, TomC
Tom & Donna Christman. 1985 Kenworth 40ft Super C with garage. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline papatony

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Re: 4104/4106 Question - mountains
« Reply #4 on: February 12, 2011, 07:59:47 AM »
Is there a ten speed trans. that will replace the 4 speed on a 4106  '64

Offline RJ

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Re: 4104/4106 Question - mountains
« Reply #5 on: February 12, 2011, 09:19:50 AM »
PapaTony -

With the GMC V-drive powertrain, you have your choice of three transmissions:

1. Stock manual 4-spd.

2. VS-series two-spd automatic

3. V-730 three speed automatic.

If you want to put a 10-spd in one, you'd have to completely rebuild the rear of the coach to convert it to a T-drive configuration.

Sorry.   :'(

FWIW & HTH. . .

 ;)
1992 Prevost XL Vantaré Conversion M1001907 8V92T/HT-755 (DDEC/ATEC)
2003 VW Jetta TDI Sportwagon "Towed"
Cheney WA (when home)

Offline RJ

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Re: 4104/4106 Question - mountains
« Reply #6 on: February 12, 2011, 09:22:29 AM »
Mike -

The simple answer to your question?

Fine.

You just get to putter along climbing the grades out here in 2nd gear, while enjoying the beautiful scenery!

Think "The Tortoise and the Hare" if it's a 4104.  The other two will be a little faster, but not much.

FWIW & HTH. . .

 ;)
1992 Prevost XL Vantaré Conversion M1001907 8V92T/HT-755 (DDEC/ATEC)
2003 VW Jetta TDI Sportwagon "Towed"
Cheney WA (when home)

Offline zubzub

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Re: 4104/4106 Question - mountains
« Reply #7 on: February 12, 2011, 10:00:14 AM »
From everything I have read and witnessed any bus built for revenue service will do  the job.  I have crawled,,,and i mean crawled up some steep steep hills in an old '04 in Mexico.   The mex hills are way steeper than anything I have seen in the US or Canadian rockies.  My 2 cents is get the bus that is ready to roll in good condition and go from there.  The '04 is slower, but the inline 6 is way easier to work on.  "Startability" is a bit of an issue but as long as you are rolling you should keep going.  I personally prefer the simplicity/reliability of a manual trans, wish my '04 had a splitter, but so it goes.

Offline RnMAdventures

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Re: 4104/4106 Question - mountains
« Reply #8 on: February 12, 2011, 04:36:37 PM »
Thanks for every's response.

I do like the simplicity of the DD671, but the part that I didn't like was it could get stuck when the back tires would "cup". Thats the part that worried me at times. I learned to dig it out and park more stategically. I would wonder what would happen if I was on a steep grade on mountain pass and for what ever reason I had to stop? However, I was able to take off from some very steep hills, so I suppose it wouldn't be so bad. I love the sound of a DD671.

My wife will be driving the bus as well (she insist). I figure the experience would be better for her if it is an automatic, but she told me she can drive either. There is a 4106 I plan to look at soon that has an automatic. It's a quality conversion and I almost purchased it years ago. I am ready to take the family on some traveling adventures.
Mike & Rosemarie
1964 PD4106-2626
DD8v71 & Allison v730

Offline gus

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Re: 4104/4106 Question - mountains
« Reply #9 on: February 12, 2011, 07:57:34 PM »
Mike,

I've driven my 4104 round trip across the Rockies six times in five years with no problems other than going very slow upgrade!!

The problem is not a 671, it is the poorly geared Spicer. Mountains are not the problem, a too high first gear is the problem.

You have to be very careful about where you stop whether on a mountain grade or a steep incline out of a parking lot!! You just can't start from a stop on anything steep or soft without damaging the clutch and doing possible harm to the engine. Slipping the clutch is a no-no although sometimes you have no choice.

The upside of the Spicer is good fuel mileage and good engine braking on downgrades. Also it is kind of fun to shift when it and the clutch are properly adjusted. When the clutch is out of adjustment it is miserable.
PD4107-152
PD4104-1274
Ash Flat, AR

Offline Barn Owl

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Re: 4104/4106 Question - mountains
« Reply #10 on: February 12, 2011, 08:23:14 PM »
Quote
long as you are rolling you should keep going.

Good strategy but Murphy's Law will kill any good plan. Start overheating on one of those long steep grades and you are going to stop to cool off, like it or not. Or let a bear become visible from the road and every gawker in front of you will stop to take a photo and cause you to have multiple stop/starts, no matter how much horn blowing everyone is doing. The list goes on but you get the idea. I don't find the 4106 very difficult to work on. The starter would be the only thing that is not accessible from the back. I like the fact that you can raise the rear engine lid and work standing up without getting rained on. GMs are a dream to turn wrenches in compared to some other manufactures. Yes, I am biased to GM for these good reasons and some others that might just make no sense at all. Owners tend to think that their manufacture is the best ever and I am no exception. I will say that I could be happy with just about any decent conversion regardless of manufacture.
L. Christley - W3EYE Amateur Extra
Blue Ridge Mountains, S.W. Virginia
It’s the education gained, and the ability to apply, and share, what we learn.
Have fun, be great, that way you have Great Fun!

Offline JohnEd

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Re: 4104/4106 Question - mountains
« Reply #11 on: February 12, 2011, 09:39:29 PM »
I was told by a well experienced 4106 pilot that starting a Spicer on a hill was a cinch. ???  So here is the procedure....

First, you have to modify your engine to allow the fast idle to be  engaged AND be able to put the trans in first gear.  Normal mode, I am told is that the engine will drop out of fast idle when the trans is shifted into gear.  I think safety is the reason for that lockout.

On the hill, while stopped, you engage "fast idle".  You then shift into first.  Ease the clutch out and let the governor walk you into the start.  Absolute minimum clutch slip.  Add some throttle to come up to speed and switch off the fast idle and shift when possible.  I have never done this nor have I driven a 04/06 but that man has street cred with me and I will repeat this "lie" with confidence.

I once described this "method" on this board and was come down on like a ton of bricks from a couple old salts.  I am not smart enuf to argue with anybody DD savvy or truck wise....so I won't.  They never did come up with an explanation of just why this procedure was "crazy", their word, or why DD had locked out the fast idle while in gear.  That is the advocated way to start out on the level but not using the fast idle.  Remember being advised "let the governor get it moving and save the clutch"?  I was told that starting on a 6% grade was a non event and that you could easily start on a steeper grade using the Governor.  Like I said though, I never did it.

BK?  Tom?  BW?

Good luck,

John
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The price of apathy towards public affairs is to be ruled by evil men." Plato
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Offline pvcces

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Re: 4104/4106 Question - mountains
« Reply #12 on: February 12, 2011, 10:43:00 PM »
Hi, John.

I'm afraid that I'm the one that told you about using the fast idle for getting rolling on an upgrade. For some reason, our fast idle was working when we got the coach and the circuit to shut it off when the emergency brake was released had been bypassed. In the process of learning to drive our coach, I discovered how to use the fast idle.

First off, I rarely use that method because it does raise some safety questions. But, if I don't think ahead when stopping on an upgrade and the coach doesn't want to get rolling with a dead throttle start, the fast idle will do it. One thing that isn't obvious, is that the 8V71 in stock configuration will produce 90% of maximum torque at around 800 RPM, a little less than the fast idle speed.

The other thing is that the clutch will try to buck or chatter some when letting the it engage at an idle. When the fast idle is turned on, then the clutch engagement is smooth. I think that the engine moves around a bit on the cradle, changing the length and throw of the linkage slightly. With the fast idle, the throttle has no effect on the governor, because it is locked.

To use the fast idle to get rolling, I have to ease the clutch all the way out in first, shut the fast idle off and hit the throttle at the at the same time. If I do it right, there's only a slight lurch while shifting from fast idle to normal throttle.

While the engine is not hard to stall when idling at about 450 RPM, it's another story altogether on fast idle. I expect that's the reason that the fast idle is usually disabled when the parking brake is released.

That's probably more than you wanted to know about the fast idle operation.

Tom Caffrey
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska

Offline Rick59-4104

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Re: 4104/4106 Question - mountains
« Reply #13 on: February 12, 2011, 10:44:13 PM »
 JohnEd,
  Your description of using fast idle and starting the coach on a grade in first is what I do when I start the bus on a grade.....works great for me and I have got the 4104 rolling on some pretty steep grades here in the Ozark Mountains.  And please before anyone jumps in and starts the old "your in the Ozarks, there aren't any steep grades in the Ozarks" argument...... yes Helen there are some very steep grades here in the Ozarks. ;)  I say this and I have traveled a lot in the Mountains of Colorado, Wyoming, Arizona and New Mexico.
There is a saying here, our mountains may not be very tall but the valleys sure are deep.
 I do not know if my coach has had any thing done to it to allow the use of fast idle when in gear I just assumed it was normal. I can get the coach rolling using fast idle and throw the fast idle off as I engage the foot throttle to pick up speed..Works great.

Rick
NW Arkansas
1959 GM 4104  No. 4115
1972 Grumman Kurbmaster Stepvan Conversion
1957 Airstream 13 panel Overlander

Offline JohnEd

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Re: 4104/4106 Question - mountains
« Reply #14 on: February 12, 2011, 11:01:47 PM »
Hi Tom,

I remembered where I heard it and having ridden with you I can attest that you know what you are doing behind the wheel as far as my "feeling" goes.  Didn't want to take unauthorized use....

So what is the "dangerous" aspect?

Rick,

Do you need to be extra cautious to switch off the fast idle when you depress the throttle?  Can't you just sw off and depress throttle?  More casual like?  Thanks for your contribution.

Considering I used to hear that if you got stopped on a hill you might have to back to the bottom of the hill and get a run at it this takes on new meaning.  A three mile "back down the mountain" might sound like a real pain in the tookus but now just consider the ramifications if you are alone and pulling your toad 4 down...or even 2.  Now that is a bonefide delema in my book.  I think many will benefit from this discussion and if you need to be special careful...well, so be it.

Thanks again for your comments and thanks to Tom one more time.
"An uneducated vote is a treasonous act more damaging than any treachery of the battlefield.
The price of apathy towards public affairs is to be ruled by evil men." Plato
“We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light.”
—Pla

 

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