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Author Topic: automatic vs 4spd  (Read 7591 times)
1960eagle
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« on: March 17, 2010, 06:42:44 PM »

Greetings.I am considering going with auto trans to swap out the spicer 4spd.Kind of wondered about doing it with the 8v71n having only so much power,and loss of mpg.anyone who has done the swap out with pros&cons?     Thanks.
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Lin
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« Reply #1 on: March 17, 2010, 07:34:37 PM »

I am in the process now.  There may be some loss of power and mileage, but I am not convinced it will be noticeable.  In my case, I am expecting an increase in power because of going from C60 to N65 injectors.  I also contend that there should not a loss of mileage since the extra power may
let me travel the hills one gear up.  Still just hypothetical though.  Aside from the convenience of the automatic, I consider the Spicer 4 speed a lousy choice.  The low gears are just too high to be dependable in hill country, especially if you need to stop and start on a serious grade.  If one were in a traffic jam going up the Grapevine, you would be able to calculate miles per clutch.  I have also been on hills that the Spicer could not even make in first and had to back down.  I did barely get over it with a one half mile racing start though.
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Melbo
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« Reply #2 on: March 17, 2010, 07:51:55 PM »

I drove a worn out 71 with a spicer and did fine but the engine would overheat

The cost of the rebuild and trade out to an auto was about the same as a complete repower and trans change

I now have a cummins L10 with a ZF tranny ( don't google tranny )

The 71 was max a 318HP and the L10 is 275HP and doesn't overheat.

I got MAX 6 mpg from the 71 more realistically 5 and now 6 is my minimum -- typically  up to 7

I live in NM and drive the mountains any direction I travel and like my setup

YMMV

HTH

Melbo
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luvrbus
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« Reply #3 on: March 17, 2010, 08:23:01 PM »

1960, your not going to see much difference in fuel or power with a automatic your 71 without the double cooler some type cooler for the transmission will be needed but cooling the engine on your Eagle is not going to be a problem it is the MCI guy's that have that problem.
If it were me and that 01 did not have power steering I would spend the bucks on power steering before a automatic.




Mel, when you leave exit 153 heading west which one of the 3 lanes are you in I am in the left lol.
 I'll be there Mon everything is close to normal here now and I will call you when I get there and you , Eddie,Jim and myself will have lunch if you are around.
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« Reply #4 on: March 17, 2010, 08:59:02 PM »

Clifford

I live in the right lane but if I am really in a hurry I should be driving the Zcar not the bus

I look forward to seeing you when you get here

Melbo
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If it won't go FORCE it ---- if it breaks it needed to be replaced anyway
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1960eagle
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« Reply #5 on: March 17, 2010, 09:10:34 PM »

What type/price would be good for p/s ? I get about 10-12 mpg right now with the 4spd and would rather have air throttle and power steering.
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luvrbus
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« Reply #6 on: March 17, 2010, 09:26:15 PM »

Eagles take Ross power steering find a truck wrecking yard and buy one from a R series Mack truck bolts up to the bracket that will need a little reinforcement not a real big job but not easy running the lines to the front.
Pratt on the Eagles board has a complete air throttle for a Eagle with a 8v71 listed there in the mall for 250 used very little. 


good luck
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busguy01
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« Reply #7 on: March 18, 2010, 06:00:05 AM »

With a 01 you can go to a 60 series with automatic and will think you have a whole new bus! I did so back in 2001 and glad I did it. Was an easy install and made the Eagle into a great unit.  I think it can be done for the price of a good overhaul and auto install if you can do the work yourself. Took me about 40 hours over a month or so. At a later date I changed the rear end to a 3:36 but now that prices have gone down on B500s the would not be needed. I know where a low milage 60 series and B 500 are for sale for $10K.
Just a thought. By the way -- be glad you have an 01. With the tag behind the drivers it opens up a lot of change over possibilites.
JimH
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Started with nothing - still have most of it left!
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MCI EL3 in progress. raised roof & Slides
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« Reply #8 on: March 18, 2010, 06:17:40 AM »

Hey Noel,

These are my thoughts for our needs. My "Armstrong" steering works great. I'll change it over to power after I put in an Automatic. For me the auto comes first, I'll explain why.

Our intentions are to pull an enclosed trailer, with toad and stuff. I'll stay away from big, long hills when I can. We live in ours fulltime and I need more space for projects and tools.

The auto for us is a must for even the sligthtest grade pulling a trailer. When on short trips we'll just pull the toad. I'm building a hitch right now and have the tow bar.

First gear in a spicer is too high, fourth gear is rediculous. I just don't like the thought of smelling a burnt clutch. It should bring me some fuel money at the local recycler, otherwise it's just a boat anchor. Our temps have never gotten over 180 with our 8v71N, hoping to add a turbo at a later date.

All of this is always subject to change, as we'll do it our way! Grin

Paul
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« Reply #9 on: March 18, 2010, 08:33:41 AM »

We each do it different but if I had a 8v71 and a bus with no power steering I would install the steering and install a 9 or 10 speed in mine you can buy a Road Ranger for 300 bucks and it is a big improvement for a 8v71 and a easy install plus you have a range of gears to choose from, Bob Gilbert is out here running the hills and mountains with his 8v71 and 10 speed in his Eagle and having no problems


good luck
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1960eagle
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« Reply #10 on: March 18, 2010, 08:56:42 AM »

I like your idea of 60series and automatic jimH,however i am a little concerned about the brakes on my 01,they are not really what i would call great.they work ok just wish i could beef up the action.have adjusted them but havent driven it since adjustment.I dont like feeling that pucker up feeling when braking! I do like the roadranger 10spd idea,dont know about my single rod shift rod and how that would workout?  Ideas?       thanks
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luvrbus
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« Reply #11 on: March 18, 2010, 09:07:14 AM »

1960, you are not going to have great brakes on the 01 till you upgrade to the late model 05 or 10 shoes and drums not enough shoe or drum surface on the 01 for great brakes.
Do you have a Jake it will help some


good luck
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TomC
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« Reply #12 on: March 18, 2010, 09:30:22 AM »

1960-if you do switch to an automatic (the HT740 is the best choice-HT754CR is the close ratio 5spd, but it isn't as robust as the 4spd HT740), I highly recommend you keep the C60 injectors just to try, since there is definitely a fuel mileage hit going to the N65's since injector timing is different.  I had brown tag N65's in my bus and got 4.5-6mpg.  I have since turbocharged and air to air intercooled the engine with 9G75 injectors.  I still get 4.5-6.5mpg, but the performance difference is remarkable-without any change in altitude.
I like the Allison automatics so much, on my Kenworth truck conversion, I took out the 13spd overdrive manual and replaced it with the HT740.  Man, what a performance difference.  I can accelerate with cars from a signal (course I'm only 28,000lbs without anything installed yet).  And I do know how to shift.  When I removed the 13spd, my truck had nearly 1.2 million miles on it with the original clutch-and there was still some wear left on the clutch lining.  If you do anything-install the Allison automatic, it will make driving a real pleasure, with backing, starting, and stuck in traffic no big deal.  Good Luck, TomC
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« Reply #13 on: March 18, 2010, 09:50:59 AM »

Noel, one more comment then I'll leave $500 vs $5000 it your call with the $500 giving you better results if you don't mind shifting gears btw I have a Allison in my Eagle



good luck
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Lin
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« Reply #14 on: March 18, 2010, 10:18:04 AM »

Clifford is sure right about there being a large cost difference.  However, I do not think it is totally fair since it compares the price of rebuilt Allison to a takeout Road Ranger.  If you go with rebuilt, the RR is going to be above $2000.  Also, if you plan on changing the clutch at the same time, you can add from $1000.- $2000. depending on whether you do the installation yourself.  For me, since the whole project started with needing a clutch and I do not do that work myself, the clutch cost became a credit toward the Allison.  This is with an MC5a though, so you should adjust my figures to your model.

Oh, and one other thing.  Which transmission do you want?  Even if you are saving money with the manual, if it is not what you want it is somewhat of a waste, n'est pas?
« Last Edit: March 18, 2010, 10:25:47 AM by Lin » Logged

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