Transmission Upgrade/change

[George Lowry]

I have always been told that the Detroit Two Strokers like it best
when the throttle is to the floor. Some said that the worse you treat
a women, a dog, and a Detroit two stroker, the better they like it.
Haven't got the skinny on the four stroke Detroit yet....

George Lowry
'95 WBDA 4203 & GM 4106 (for sale)
Spearfish, SD

randydupree wrote:

> the early pts would run 70 mph,wfo..with stock gearing..they were built during
the 55mph days too. the fc's with a turbo will run that fast too..no matter
what,you don't want to run your engine with the pedal on the floor.
randydupree93wb
> ----- Original Message -----
> From: freewill2008
> To: WanderlodgeForum@yahoogroups.com
> Sent: Thursday, June 02, 2005 6:28 PM
> Subject: [WanderlodgeForum] Re: Transmission Upgrade/change
>
>
> I've not heard any complaints about the many Birds that have been
> changed to taller gearing. Apparently a 4.11 or 4.44 will still pull
> steep grades in the Rockies. Does anyone have a guess as to why BB
> chose such low (high numeric) ratios for the FC buses?
>
> It has occured to me that these rigs were built during the 55 MPH
> national speed limit, but that didn't stop BB from buiding PTs that
> would run 75 MPH all day.
>
> Bob Griesel '84 FC31 WLII MT643/4.88 11R22.5
>
> --- In WanderlodgeForum@yahoogroups.com, "Jeff Miller"
> wrote:
> > Adapting an MD-3060 to the 3208 will be an expensive conversion
> after
> > the electronics etc.
> >
> > Although the MT643 is not a high-tech transmission, there are other
> > (read: cheaper) ways to skin that cat. If the MT-643 is still
> > servicable, you might start with a good checkup including fluid and
> > filter change, might improve your shifting, might need work on the
> > modulator?
> >
> > As far as the addition of an overdrive and lower diff gears, it
> > sounds like you'd be spending a lot of $$ and expecting more than
> > you'll get. You would be saving money to add an overdrive.
> >
> > I've changed gearing, run the 3208/FC from 210hp (Na) to 300hp
> > (ATAAC) with 5.29:1 gears to 4.11:1 gears, MT-643 and HP-500
> w/ .83:1
> > overdrive. The simple things I've learned are that 1) gearing
> doesn't
> > add power, 2) even with 4:11 diff gears you don't run out of low-
> end,
> > 3) there is a sweet-spot, depending on many factors such as
> intended
> > cruise speed / intended load / expected terrain, and 4)
> Experimenting
> > is very expensive.
> >
> > As far as your goal of a reliable transmission (1 below), a reman
> MT-
> > 643 with a warranty will cost you less than the electronics for the
> > MD-3060 (probably).
> >
> > Goal 2, faster top-end, an overdrive will help but so would 4.44:1
> > gears which should cost less than $2k. If the gearing spreadsheet
> is
> > no longer in the files, I can try to submit it again, or I could
> > email it to you.
> >
> > Goal 3, pulling better on hills. This is a matter of gearing, you
> > have lower gears in the transmission. If you run below 1st gear,
> then
> > you're in trouble, I didn't have that problem pulling 14% at
> 10,000ft
> > with my 210/Na so I doubt you will with a turbo. I found that
> taller
> > diff gearing can actually help somewhat on hills, I was able to
> > downshift into 3rd at a higher speed and hold a higher speed.
> > Climbing is largely a product of your power to weight ratio, and
> > gearing doesn't help that (unless you can't stay in the high end of
> > the power curve, which on the 3208 is at max. RPM).
> >
> > I don't mean to discourage your project, I'd rather have a MD-3060
> > than an MT-643, but unless you can do it really cheap I just don't
> > see the return on investment either in coach value or performance.
> >
> > - Jeff Miller
> > http://www.wanderlodge.net
> >
> >
> > --- In WanderlodgeForum@yahoogroups.com, "hsaddock"
> > wrote:
> > > Folks:
> > > I am giving serious thought to changing the transmission in my
> > > 83FC35 from the Allison MT641 to an Allison MD3000. The reasons
> > > are: 1) current transmission with 112K miles on it shifts a
> little
> > > slowly from 1st to 2nd at full throttle - it shifts just fine if
> I
> > > back off the throttle slightly and in all other gears. (perhaps
> > this
> > > is the beginning of a bigger future problem?) 2) I want to travel
> a
> > > little faster at top-end, and the MD3000's 5/6 speeds gives the
> > > overdrive(s). 3) I want to pull a little better going up steep
> > > hills so if I lower the differential ratio while doing this
> > > conversion, I can pull better in the lower gears and still tool
> > down
> > > the road faster on the flats with the overdrives.
> > >
> > > Has anyone tried this conversion? Comments on anticipated
> issues?
> > > The MD3000 appears to be an inch shorter in length than the MT641
> > > and a similar bolt up pattern so I don't expect to see any major
> > > issues with mounting. The MD3000 is computer controlled - can it
> > be
> > > fooled into working with an older 3208?
> > >
> > > Harry Saddock
> > > 83FC35
> > > South Windsor, CT
>
>
>
>
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