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Author Topic: Advice on converting a manual to auto  (Read 1309 times)
Geom
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« on: July 23, 2013, 08:18:12 AM »

Hey guys, need some advice. A couple of the coaches we're considering are quite nice, but come with manual transmissions. While we're ok driving a manual, at least for a little while, at some point we'll probably want to eventually replace it with an automatic. So I'd like to get an idea of how much that would cost for comparison to ones with auto already.
Not really looking for shade-tree mechanic pricing where I would be doing a sizable amount of the labor, but for the pricing of having a professional do the work.

This would be for a GM 41xx coach (non 4104) with either an 8v71 or 6v92 engine, and most likely a 730 transmission. Assume a modest age, recently rebuilt transmission.

I realize there are probably going to be a lot of variables to keep in check, but I'm just wanting a representative ballpark number for planning/budgeting purposes.
I'd like to know the expected/reasonable cost of the hardware and the expected/reasonable amount of labor involved.

Thanks in advance,
George
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1966 GM 4107
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luvrbus
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« Reply #1 on: July 23, 2013, 08:50:44 AM »

All depends on the shop and if they use a rebuilt or used 730 it will be around 10 grand a lot of parts to gather up to do that conversion to generate more heat Roll Eyes
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Geom
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« Reply #2 on: July 23, 2013, 09:21:20 AM »

All depends on the shop and if they use a rebuilt or used 730 it will be around 10 grand a lot of parts to gather up to do that conversion to generate more heat Roll Eyes

It sounds like it's a bit more involved than I had originally thought.
I gather the engine will have to come out I assume?

Is the 10 grand just in hardware (tranny and misc parts), or the sum of hardware and labor?

What's a good estimate on the number of hours involved?

Thanks

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luvrbus
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« Reply #3 on: July 23, 2013, 09:56:35 AM »

40 hrs that flywheel for the 730 is well over 100 lbs just 1 big piece of iron there is a lot involved like changing the rear engine seal to a 2 way seal, building support brackets, reinforcing the bulk,shift tower,cables,cooler,drive shaft a lot of extra items 

Thinking about it now I don't believe I would do one for 10 grand furnishing the parts   
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LowTide
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« Reply #4 on: July 23, 2013, 10:53:56 AM »

40 hrs that flywheel for the 730 is well over 100 lbs just 1 big piece of iron there is a lot involved like changing the rear engine seal to a 2 way seal, building support brackets, reinforcing the bulk,shift tower,cables,cooler,drive shaft a lot of extra items 

Thinking about it now I don't believe I would do one for 10 grand furnishing the parts   

I know one day we will probably change over to automatic once I have issues pushing that clutch in, hopefully by then senior citizen discounts will be available.....LOL

Cliff, we are going to have to do that lunch we spoke about a while back. I have been so dog gone busy with the border stuff and everyday signs that I just can't seem to get a break.
I am at the point that the lunch is sounding better than the job.....if you know what I mean Wink
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« Reply #5 on: July 23, 2013, 12:32:34 PM »

Hi Geom,
It is very hard to find anything more efficient than hardened gears turning in oil.  You'll use more in fuel and maintenance with any auto than a stick.  "Stick" with what you've got. :-)
Frank
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Len Silva
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« Reply #6 on: July 23, 2013, 12:44:26 PM »

If you are looking at a 41XX, then obviously you are looking at a budget coach.  Personally, I would stick with the stick, but if you are sure you are going to want an automatic, find one already done.  I would also suggest a coach that was born with a factory automatic rather than a conversion.  It will be far cheaper in the long run.
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bevans6
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« Reply #7 on: July 23, 2013, 12:52:54 PM »

These days I would absolutely look for a bus that had what I want.  Even if the premium for getting a bus with a factory automatic was 10 grand compared to the same bus with a manual (and I don't think there really is a premium at all) you'd come out ahead with a factory install and no fuss finding the shop to do it.

When my leg goes (and it's a good thing the clutch is on the left because my right knee is giving me fits right now, starting to regret buying a house with stairs, in the mornings) I will have engineered an electronic servo driven clutch.  Or an air clutch.  Or a hydraulic ram clutch.  The pedal pressure will be such that I will be able to clutch in/out with my big toe...   Grin

Brian
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1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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« Reply #8 on: July 23, 2013, 02:28:52 PM »

Simple answer: don't buy a bus with a manual. There should be lots of buses to look at with automatics.

JC
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JC
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chessie4905
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« Reply #9 on: July 23, 2013, 02:56:49 PM »

  Also the 4106 has a dry clutch, I believe. If so, then the bell housing on engine needs some aluminum welded in to seal it up around starter area and a sealed starter drive. The 4905's have oil clutch, so this isn't needed.  With that auto, expect to lose 6 mph top cruising speed and about 2 miles per gallon. If you really want to do this, it would be easier to get the parts off a donor bus. Unless you can mechanically tackle this yourself or related to Luke or Luvrbus, Find one that already has an auto or learn to drive a standard for now and enjoy the better fuel mileage. Look for one with an auto as your second conversion after you decide you really like this life$$$$style/ Hobby$$$$$.
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Lin
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« Reply #10 on: July 23, 2013, 07:07:00 PM »

We bought our 5a with a stick with the idea of changing to an auto later. When the clutch failed, we made the change rather than put any money into keeping the Spicer.  Get one with a auto already in it.  It will be far cheaper in the long run.  There may be some mpg lose, but ours was insignificant if any.  You do not lose any mph since the Allison would be running in lock up.  If there is such a lose, we certainly have not seen it. What we do see though is a coach that is far more pleasant to drive and that can start moving on a hill without problems (not to mention not having a reverse the is way to fast). The Spicer may be okay for revenue service in 1965 but it is a real dog for an RV today. So I guess it depends on how you are going to use it.
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Geom
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« Reply #11 on: July 23, 2013, 07:19:10 PM »

Thanks everyone.
So it does sound like it's probably going to be more of a PITA to convert one than it's worth. It would be better to get one with an automatic already in it; if that's what we want.

That's kind of what we were already thinking but I wanted to check to make sure we weren't disqualifying good potential candidates that could be modified to suit our needs.

Although I'm sure we'd be fine with a manual, I think that an auto will be considerably more convenient going forward. We drive manuals now (in our cars) by choice, but on a bus I think I just want to be able to sit down, mash pedal down, and vroom (more likely chug) forward Wink

Thanks
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Dave5Cs
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« Reply #12 on: July 23, 2013, 07:35:10 PM »

Brian
http://www.ebay.com/itm/Harmar-SL350AC-Indoor-Stairlift-Stair-Lift-Chair-Lift-/181150891944

Your welcome  Grin

Dave5Cs
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luvrbus
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« Reply #13 on: July 23, 2013, 08:01:30 PM »

The Allison with a Stone/Bennett shifter is the only way to go in the older buses I don't want cables,rods or a shift tower just the switch on the dash works for me  Roll Eyes A 740 install in other buses like the MCI,Prevost,Eagles and others are a lot cheaper to do than a V730 in a GM bus
« Last Edit: July 23, 2013, 08:12:22 PM by luvrbus » Logged

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tekebird
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« Reply #14 on: July 23, 2013, 08:15:00 PM »

10k is very light.

My Dad just had Luke do this conversion (properly)

also keep in mind good possibility the Diff will need swapped too.......Check your final delivery record for the Diff ratio

I was the only bright one to mention that pre swap......and nobody paid me any mind......only to take delivery of a bus with a 55mph top speed....LOL

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