In summary, there really isn't an overdrive solution for a closed driveline
truck. In keeping a closed driveline, you can use the stock 3 or 4 speed
Muncie (which have less than friendly shift ratios), or a later model
Saginaw 4 speed (nicer ratios) with Patrick's adapter for the torque tube.
In any case, a 1:1 3rd or 4th makes the 3.55 ring and pinion very
attractive. Use of a later style Saginaw 3 or 4 speed overdrive would
require a late model open driveline. I suggest you browse the archives as
all these options are presented there.
Allen in Seattle
'50 3100
----- Original Message -----
From: "Thomas Allen" <thallen@nwlink.com>
To: "The Perfesser" <driver@49chevy.com>
Cc: <oletrucks@autox.team.net>
Sent: Wednesday, December 05, 2001 10:50 AM
Subject: Re: [oletrucks] Transmissions (2): Overdrive?
> Paul,
>
> Regarding your three-speed trans: As your shop suggests the basic problem
> is that the transmission is really too light duty for the job. Chevrolet
> didn't anticipate that they would be in service so long. This is basically
> the same transmission as in the cars and there were internal variations
> over the years. The second problem your shop faces is that they are forced
> to use used parts either because they don't know where to get them or they
> are unavailable. I had the problem you describe on a 48 3100 many year
back
> so the memory is a little fuzzy by now but as I remember the synchro hub
> assembly was worn and would allow the synchro ring to rotate inside the
hub
> just enough for the teeth on the synchro ring and teeth on the second
speed
> gear to become misalligned after the transmission was shifted into second
> gear. The soultion is a new second/third shift hub assembly. This is the
> gizmo that sits on the main shaft between the second speed gear and the
> main drive gear. I was in college when I had this problem and had no
money,
> so I tried various combinations of used parts until I came up with
> something that worked. At $50/hr or more you can't afford to do what I
did.
> So go find a new shift assembly. going to the 48-66 Saganaw 4-speed is an
> option as these were offered in the half tons and can be found with the
> bell on the end for the torque tube. You won't wear one of these out with
a
> 6 cyl in a half ton. Try to get on that came out of a half ton rather
than
> a 2 ton.
>
> -Tom
> 51 3800
>
> At 10:57 AM 12/5/01 -0600, The Perfesser wrote:
> >Hello again,
> >
> >In addition to the preceding magnum opus about transmissions and drive
> >chains, one of my advisors has suggested I research transmissions with
> >overdrive as an alternative to changing the ring and pinion in the rear
end.
> >
> >Are there any transmissions with Overdrive that might be suitable for a
> >truck such as mine (1949 3100) ?
> >
> >The thought is that if I'm going to have to replace the transmission, I
> >might consider doing it with one that offers over drive;
> >The suspicion is that overdrive, if it exists at all, did not come along
> >until much later, and so would likely not be compatible with my old-style
> >"closed" drive shaft.
> >
> >You know how it is with the old girls... tummy tuck here requires a thigh
> >lift there...
> >
> >--PS
> >
> >
> >- - - - - - - - - - - - - - - - - - - - - - -
> >Paul Schatzkin, aka The Perfesser
> >http://www.theperfesser.com
> >
> >1949 Chevy 3100
> >http://49chevy.com
> >oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
> Tom Allen
> Seattle, WA
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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