Manual Transmission for FC (was Re: Question for John H.....)

[Mike Hohnstein]

google Tuthill Contols. My unit is a RTO6613, all I know is it drops 500 rpm
when I grab OD and I did break in on the propane.
MH
----- Original Message -----
From: Donald Watson
To: WanderlodgeForum@yahoogroups.com
Sent: Sunday, December 30, 2007 9:52 AM
Subject: RE: [WanderlodgeForum] Manual Transmission for FC (was Re: Question
for John H.....)


Mike - What "cables for the shifter" are you referring to? Is this some
mechanical device to replace the shift tower we're familiar with in
tractors? If this FC of yours is the coach with the 4.88 gear set, a single
overdrive gear would give a gear reduction of .87 or a final result of 4.24.


According to the following current Roadranger publication, these are the
ratios for current 13 speed transmissions:

http://www.roadranger.com/ecm/groups/pub...ents/conte
nt/rr_rrsl-0001.pdf

7th over (11th gear) = 1.00 (direct)
8th direct (12th gear) = .86
8th over (13th gear) = .73

I'm not sure why 7th over is direct. This reminds me of RTOO
(double-overdrive) gearing. I mention RTO series because that was what I
was familiar with and what are readily available, but Eaton/Fuller now offer
a newer series of transmissions with higher torque ratings. The 18 speed
transmissions now split the lower range which I find desirable for heavy
loads, but not necessarily of interest in our application.

This Eaton publication probably gives a more realistic representation of
what one would find in a used RTO 12513

http://www.roadranger.com/ecm/groups/pub...ents/conte
nt/rr_apsl-0189.pdf

7th over (11th gear) = 1.34
8th direct (12th gear) = 1.00 (direct)
8th over (13th gear) = .87

I guess I'll have to play with a spreadsheet and figure out what rpm/speed
I'll find in each gear based on various rear end ratios. I appreciate
Mike's input on this topic.

Donn
'76 FC33
South Kingstown, RI

From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of Mike Hohnstein
Sent: Friday, December 28, 2007 11:35 PM
To: WanderlodgeForum@yahoogroups.com
Subject: Re: [WanderlodgeForum] Manual Transmission for FC (was Re: Question
for John H.....)

I wuz under the bird measuring today. Looks like it will be pretty easy to
do the change. The manual trans is pretty close to the Allison dimensionally
and there is plenty of room to run the cables for the shifter. It should be
noted the front axle gets in the way of removing the trans. Looks like 8
bolts and the axle will drop down to allow access.
I will have, excess to my needs, a low mile reman 643 with the drive line
brownie box over drive and air shifter and the custom drive shafts to effect
a "bolt in installation" in any FC available. The effect is an 8 speed
Allison. I will be undertaking the project in the fall of 08.
MH
----- Original Message -----
From: Donald Watson
To: WanderlodgeForum@yahoogroups.com

Sent: Friday, December 28, 2007 6:08 PM
Subject: [WanderlodgeForum] Manual Transmission for FC (was Re: Question for
John H.....)

This topic has certainly received my attention, especially as I have not yet
changed my 5.29 rear and the last gear of a new transmission would dictate
the proper rear ratio. The bulk of my over-the-road experience was with a
13 speed. These 12513 Roadrangers are readily available. I wonder about
the travel and shape of the gear shift lever Mike has fashioned. He has
apparently done some engineering.

My Wanderlodge parts book depicts the clutch pedal assemblies of FCs with
manual transmissions. I have a Peterbilt conventional with a 3406B Cat and
12515 15 speed (10 speed normal with 5 speed deep reduction). I could study
the parts involved and learn more.

Mike once mentioned a problem with resale which might be valid. I wonder
how much deterrent a manual transmission would be if it was dialed in
correctly and gave the operator more control, more torque when necessary and
lots of top-end when the terrain allowed it. Personally, I'd be willing to
spend the money and labor to perform the 'upgrade'. I'm just not sure how
much work engineering the clutch would entail. I assume a new bell housing
would be necessary. With proper selection of the rear end ratio, the number
of gears available would insure that the engine could be kept in the optimum
rpm range at any road speed.

This is definitely 'food for thought'.

Donn
'76 FC33
South Kingstown, RI

________________________________________
From: WanderlodgeForum@yahoogroups.com

[mailto:WanderlodgeForum@yahoogroups.com
] On Behalf Of Mike Hohnstein
Sent: Tuesday, December 25, 2007 3:37 PM
To: WanderlodgeForum@yahoogroups.com

Subject: Re: [WanderlodgeForum] Re: Question for John H. on his
Wanderlodge's Extended Gri...

I hear that. I bought my first medium duty truck due to it's Allison 653.
Some time later I was brought up to speed with my first 10 speed rig.
----- Original Message -----
From: bubblerboy64
To: WanderlodgeForum@yahoogroups.com

Sent: Tuesday, December 25, 2007 2:08 PM
Subject: [WanderlodgeForum] Re: Question for John H. on his Wanderlodge's
Extended Gri...

Mike, Most people do not want anything to do with a manual shift
anything these days but I have to agree that these old FC BB's are
dying to have a better transmission. Keep me in the loop. In other
words. You work out the bugs and the details and maybe down the
road....
John Heckman
central Pa
1973 FC
>
> I had a CVT in my Honda Civic Hybrid. A great concept, worked well
in the small car. It seems the OEMs are having problems with CVT as
power and weight increase. Probably why you see 6 speed and even
some 8 speed automatics becoming more common.
> My experience with the 10/13 spd had led me to the conclusion that
nothing else will work for me.
> A 13 spd with OD is the perfect transmission. Ya can back up at
walking speed in LL reverse and top over 90 in 13 over. It don't get
better than that in my world.
> As a side light, I can offer this experience we had with the race
car early in the season. Car ran 9.0 @ 150 mph with the 5 speed
manual with air at 1000' corrected. Put a youngster in the car and
chose to change to a T-400 with 8" converter. All produced in my
shop so we know what the set ups are. Way too hard to find a
youngster that can even drive a stick let alone under stand
what "power shift" means. I do require he shift the auto matic by
hand however. At any rate in comparable conditions the car lost 4
mph and about a tenth of a second, or a little over a car length at
the stripe. It's all relative you know.

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