At 10:46 AM 1/30/01 -0600, you wrote:
>I WISH first gear was as much as 6:1. It isn't. The best in a Ford 5
>speed is 4.72 in the 3/4 ton, only 3.92 in the 1/2 ton 5 speed
>transmission. I figure its important to have an overall ratio (first
>gear and axle) in the range of about 20:1 for starting loads. Hence the
>4.10 axle gears with the 3.92 first gear in my F-150 that seems to work
>well. At least that's 16:1. Choosing the axle ratio is a compromise
>between starting and cruising speed because the range of ratios in the
>modern transmissions isn't as wide as I wish.
You prodded me to double check my service manual:
The NV 4500 (heavy duty, i think there are 2 versions)used by Dodge in 3/4
ton diesel vehicles has a low gear of 5.61 which is quite adequate. The
reverse ratio is 5.04 and I wish it was a little stronger.
My personal subjective test is to see if I can start moving on a grade with
a fair size trailer at idle.
The low and reverse ratios in the speed NV 5600 6 speed are both 5.63.
Unfortunately not available at the time I ordered the truck and still hard
to get.
Couldn't find the spec on the old chev. but I believe it is slightly
stronger in both low and reverse.
It also appears there is an NV 3500 manual which I assume to be used in
lighter vehicles. It is available in both a wide ratio (4.01 low,
questionable) and a close ratio with a 3.48:1 low. , even worse.
GM also uses some New Venture transmissions but the ratios may not be the
same.
It would appear that one must be careful when buying a lighter than 3/4 ton
vehicle with a manual transmission.
It appears that todays crop of gas engines are quite happy running at
higher RPM and deliver there best power there. Certainly more economical
that those of old.
In my case I have a diesel and do not like to see the cruising engine speed
over 2000 RPM
Rick Davis 1602
Jamestown, Tn
54 safari
69 Ambassador
70 Globetrotter
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