In Washington you will have to go with the electronic option. When I
thought my Speedometer sensor was going out I found out that only
licensed speedometer shops can do anything with them, auto parts
stores don't even sell them, fortunately in my situation all it took
was a couple of butt splices and some electrical tape to reconnect the
broken wires.
On Fri, May 8, 2009 at 8:42 AM, Azie L. Magnusson <maggie11@mchsi.com> wrote:
>
> teseract@moparhowto.com writes:: >>
> I've read in the archives that trucks with the 3.90 rear end with the
> stock tires (which are a good 3" shorter in diameter than my 31" tires) pull
> about 2000rpm at 60mph. This seems odd to me as the underhood sticker
> doesn't
> indicate anything about the different gear ratio - but if I had the standard
> 3.22 gears I don't think I'd be pulling the RPM I'm pulling at 60mph with
> the
> size of tires I have. <<
>
> The different tires will not make a difference in the reading of the
> speedo @ any given RPM .. You have changed the effective
> gear ratio, but the rpm of the tailshaft is still the same as it was
> before in respect to the engine RPMs.(direct connection in high
> gear with the torque converter locked up). The tires are longer in
> circumference, so you are actually moving farther(faster) @ a
> given with taller tires, but you have to change the driven gear in
> the tranny for the speedo to correct the rpms indicated @ any
> given speed.. The driveshaft is turning fewer turns to get the
> same distance, therefore the reason for having to make an equal
> correction to the drive gear for the speedo(located on the end of
> the speedo cable where it enters the tranny)..
> Anytime the tires are changed to a tire with a significant
> difference in circumference the speedo will not read correctly
> unless it has been "recalibrated" or corrected.
> There are aftermarket devices on the market that you can purchase
> that are adjustable for this type situation, but I have no experience
> with them..
> Since the '95 went to electric speedo(I think) none of this may
> be relevant.. It worked on the mechanical speedos.
>
> We could certainly slow the aging process
> down if it had to work its way through Congress.
> - Will Rogers
>
> Azie
>
>
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