Hi Karen,
The speedometer has the following parts:
There is a "worm type" gear on the transmission out-put shaft, called the
"drive gear". This gear almost never goes bad.
The drive gear turns a small gear that is connected to the cable called the
"driven gear". The driven gear could be made of nylon or plastic and it's
the gear that is changed to calibrate the speedometer with the rear. Driven
gears are made with different tooth counts, which is what changes how fast
it turns the cable. These gears are just inside the transmission case and
stay in place when the cable is removed. The square end of the cable slides
into the square hole in the gear center.
The cable connects the transmission to the Speedometer head and has small
square ends. Are the ends good?
If you disconnect the cable at both ends, does it spin freely with your
fingers? If NO then pull the cable out of the outer jacket, inspect for
frays, put some White Lube on it and re-install. If bad replace with new.
If the cable won't come out, check for a kink in the jacket. If kinked,
replace with new. Does it spin now?
Connect the cable to the Head and spin with your fingers you should be able
the "flick" it fast enough to make the needle jump. If this is ok connect to
the transmission end only and put your finger on the head end of the cable
and have someone else slowly drive down the driveway, is the cable spinning?
If not the square hole in the driven gear could be rounded out.
If memory serves me to remove the driven gear you unscrew the piece that the
cable attaches to and then slide the gear out with needle nose pliers.
I think that's all I can help with....others will "jump in" if I left
anything out.
Good Luck!
Mike Boteler
'56 4400 Stake
'56 6400 Stake
'56 8400 Wrecker
'56 9200 Tractor w/Powermatic
'57 10500 Fire Truck
Hughesville, MD
----- Original Message -----
From: "Duff Karen ES-19 103 FW/EM" <Karen.Duff@ctbrad.ang.af.mil>
To: "Oldchevytrucks (E-mail)" <old-chevy-truck@yahoogroups.com>; "oletrucks
(E-mail)" <oletrucks@autox.team.net>
Sent: Friday, May 16, 2003 9:09 AM
Subject: [oletrucks] speedometer dilemma continues
> I inquired previously about how to fix my speedometer, here are the
results:
> the cable is fine, the gauge is fine, BUT when i removed the speedometer
> connection from the transmission and pulled it out...I noticed there was
no
> gear on the end of it, and really i'm clueless as to how this thing
> works...(i know.. clueless about how anything on the truck works)....but
> first explain to me how it works, i know how the cable goes in, but it
will
> not spin...and if it did spin, how did it move the gear that was supposed
to
> be on the end of this thing? Nothing on what i removed moves.... and if
it
> is broken, can i just buy a new one?
>
> Karen Duff
> 53 3100
> 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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