Hi All,
I have a 50 Town and Country with the Fluid Drive transmission. When I
purchased the car from the second owners widow I drove the car home with the
clutch. I continued to drive the car this way until one day a friends dad
said why are you driving the car with the clutch. I said because its there.
He said that he learned how to drive on a 48 Chrysler and that if he
remembered right you did not need the clutch once you had it in gear. We
jumped in the car and at the first stop he said don't use the clutch. Sure
enough the car did not stall and from then on I knew how to drive a semi
automatic. The car shifts great and the only draw back between it and my 54
Imperial with full auto is that the exceleration is very slow on take off.
Once in second gear or forth as it is in high the car flys down the road.
Ken
>From: Bob Wilson <limoguy1950@xxxxxxxxx>
>Reply-To: mailing-list@xxxxxxxxxxxxxxxx
>To: mailing-list@xxxxxxxxxxxxxxxx
>Subject: Re: IML: Favorite Car with semi-automatic
>Date: Thu, 12 Dec 2002 17:08:10 -0800 (PST)
>
>
>John:
> "John G. Napoli" <john@xxxxxxxxx> wrote:
>It also confuses the heck out of your passengers, who can't figure out what
>you're doing. Sometimes you are using the clutch, sometimes you're not.
>Sometimes you're shifting to accelerate, sometimes you're not. I can only
>imagine what it would be like to explain it to a teenaged valet.
>
>
>[Unless you're starting in low range, you wouldn't be using the clutch]
> >
> > There is no lockup fluid coupling on either Fluid Drive or
> > Fluid-Torque Drive as there is on a modern torque converter.
> > The only '50's lockup converter I've heard of is the Packard
> > Ultramatic.
> >
>
>Correct, there is no lockup clutch. However, the nature of a fluid coupling
>(as opposed to a torque converter) permits it to effectively lock up once
>it
>reaches a certain rpm. At that point, the entire fluid mass is rotating
>around and 'locking' the driven disk to the driver. Fluid couplings have
>straight vanes, and just a driver and driven member. Torque converters have
>curved vanes and three elements. This is an oversimplification that perhaps
>someone can expound upon, but the fluid coupling does act as if it is
>locked
>up.
>
>Now, fluid couplings do not offer any torque multiplication, either. That's
>why the early GM Hydramatic automatic transmissions had 4 forward gears -
>there was no torque multiplication available to assist in getting the car
>off the line - Hydramatics used fluid couplings.
>
>[GM Hydramatics after 1961 did use torque converters.]
>
> At the other end of the
>spectrum was the GM Dynaflow, that was essentially all torque converter and
>no gears. Many, many different combinations were experimented with by the
>early automakers as they sought to find the 'best' automatic transmission
>design. For better or worse, the auto industry has evolved pretty much
>across the board to a torque converter backed by 3 or more gears with a
>mecahanical lockup element in the torque converter.
>
>[Almost no automatic with a converter and 3 speed planetaries had lockup
>except for the Packard Ultramatics which used only the torque converter
>starting out, then locked it out. It did not "shift."]
>
>I've got an old Jaguar saloon (1953, a Mark VII) with a Borg-Warner three
>speed automatic. This tranny was very advanced for its day. It has a
>torque converter with a mechanical lockup clutch (!). Why? Well, not for
>economy as today, but to minimize heat in this air-cooled tranny. The
>tranny also starts in second and shifts to third (high) when in normal
>(D)rive. Sound familiar?
>
>Was that Packard Prestomatic [Packard did not use a "Prestomatic."
>
> made by B-W? If so, it might be the same B-W
>unit I have in my Jag.
>
> > The name "Gyromatic" is exclusive to Dodge. Each make had
> > their own trade name for the semi-automatic, though the
> > technology was the same. Pre-war Chrysler semi-automatics
> > were vacuum-controlled and were hence called Vacamatics;
> > post-war were hydraulically activated Prestomatics.
> >
>
>Yes, you're right. I have been using the Dodge name - quite frankly, I did
>not know the Chrysler name. Thank you!
>
>John
>
>
>
>
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