Re: Les cars

[farna@xxxxxxx]

That's probably GM ala Allison, or a GM auto designed for big trucks (not sure if GM owned/created Allison at the time). With an auto the more speeds the bigger and heavier the thing is. I believe the 1940s eight speed was a pair of the old Dual Range Hydramatics back to back in a single case, and eventually became the Allison used in big trucks today. The Dual Range was a big heavy auto, two of them connected would be a monster! 

I've got a feeling that the six, seven, and eight speed vehicles are actually three and four speed transmissions with an OD added. The gearing is spaced so that gears can be split with the OD and the computer does all the shifting. I know the GM six speed is the three speed plus OD with split shifting. There is usually no need to split first gear, which would make a seven speed (four plus split shifted OD, no split in first). 

AMC was the first to mass produce a split shifting feature as far as I know, though not with an auto trans. The "Twin-Stick" OD shifter and trans are unique to the T-S. The T-96 or T-89 (depending on size of engine) T-S trans had a big jump between 2nd and 3rd gear so that shifting was done 1-2-2+OD-3-3+OD -- also the first domestic five speed in a passenger car (though not very quick shifting). If the T-S version trans is replaced with a standard three speed (with or without OD), one will find that thre is no reason to split second -- 2+OD and 3rd are so close that there is no reason to split shift. The same with first and 1+OD (to close to second). 

On November 16, 2005 Matt Haas wrote:

> At 07:04 PM 11/16/2005 -0500, you wrote:
> > >>Is that more advanced or is it just 'bling' in black and white?
> >
> >Peter, weeks (months?) ago, I wrote that 7- and 8-speed automatics were
> >overkill: flexibility modest, fuel-savings minimal.  Lexus' move is more a
> >signal to German manufacturers and American buyers than a mean technical
> >coup, but,   that said, in the world where more seems to mean better in
> >too many things, Japan is still in the pursuit of, ahem,
> >perfection.  Where America still needs more to be.
> <snip>
> 
> I may be mis-remembering things, but if I remember right from Autoline
> Detroit last weekend (maybe the weekend before), GM had an 8 speed
> automatic back in the 40's. That being true, how big of a technological
> feat is it for Lexus to do the same thing 60 years later?
> 
> Matt
> 
> mhaas@xxxxxxx
> Cincinnati, OH
> http://www.mattsoldcars.com
> 1967 Rambler American wagon
> 1968 Rambler American sedan
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