Classic Mustangs List Archive

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Mail From: Jerry Sevier (email redacted)

Hello all!

I am new to this list and a proud new owner of a 66 mustang 6 cyl hardtop. I
have been riding high for the last couple of days, and now is time for me to
start the restoration process. The first item of business I have is to
correct a spedometer problem. It seems, at speeds over 30, my spedometer is
about 10mph slower than the actual rate of the car.

Any ideas as to how to fix this problem? And what I need to do to determine
what it is going to cost me?

Thanks,

Jerry


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This read-only message was archived from a public mail list.
Mail From: John M. Dettori (email redacted)

On Sat, 21 Mar 1998 22:50, Jerry Sevier <(email redacted)> wrote:
>
> I am new to this list and a proud new owner of a 66 mustang 6 cyl hardtop.
> [...] at speeds over 30, my spedometer about 10mph slower than the car.
> [...] how to fix this problem? [...] cost?

Congradulations Jerry, and welcome. Basics: speedo reading depends on
1) speedometer gear
2) rear axle ratio
3) tire & wheel size
4) calibration of the gauge

Your 66 came with 14" wheels; check to see that that is the case.
A radically wider aspect ratio, i.e. 50 series, will cause error too.
If you have a data plate on the driver's door, there's a code for the
rear axle; crawling under the car will enable you to see the ID tag
on the rear axle. When you decode the codes on the 2 tags you can
determine if you have what the car left the factory with. I you have
the right tire size and the expected axle code, then you need to look
at the speedometer gear, found at the end of the speedometer cable that
plugs into your transmission. A shop manual will be helpful here. The
difference between speedo gears is the number of teeth, and they are
color coded. I believe a worn or damaged gear can cause speedo error.
If all in order, suspect the gauge itself, and have it calibrated by a
local shop.


---------------------------------------------------------------
John M. Dettori 86 SVO (2.3l IT)
Divisional VP, Program Trading 70 Mach I (351C-4V)
Paine Webber, Inc. 67 GT conv (289-4V)
New York, NY <reserved 4 67 GT500>
212 713 4683
(email redacted)
---------------------------------------------------------------


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This read-only message was archived from a public mail list.
Mail From: Wallace, John (email redacted)

-----Original Message-----
From: John M. Dettori [SMTPemail redacted)]
Sent: Monday, March 23, 1998 8:30 AM
To: Multiple recipients of list
Subject: [CM:10160] Re: Spedometer

...snip

If you have a data plate on the driver's door, there's a code
for the
rear axle; crawling under the car will enable you to see the ID
tag
on the rear axle. When you decode the codes on the 2 tags you
can
determine if you have what the car left the factory with.

...snip

Where the heck is this rear-axle ID tag? Is it on one of the
half shafts, a support somewhere, or the (pumpkin?) bellhousing for the
differential? If its on the latter, are we talking front-facing half or
rear? I have to admit, I haven't remembered to look for this tag when
I've had my car on a lift, when its easier to find these sorts of
things...but if I know where to look, maybe I'd have more luck when I'm
crawling around on the ground.
TIA,
JW
- Blue '72 hardtop, 351C

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Mail From: MrFomoco (email redacted)

Wallace, John wrote:
>

> Where the heck is this rear-axle ID tag? Is it on one of the
> half shafts, a support somewhere, or the (pumpkin?) bellhousing for the
> differential?
[....]

It should be on a pumpkin-to-housing nut...visible from
the front side, only.

MrF
-------------------------------------------------------------------------
Employee brochure: "If I were a salesman, I'd talk about..."
1966 Ford & L-M car lines (color; 7 pgs).......$14, shipped
voicenet.com/~fomoco
THE online source for 1960-1973 Ford & L-M info

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This read-only message was archived from a public mail list.
Mail From: Michael Melson (email redacted)



Wallace, John wrote:

> Where the heck is this rear-axle ID tag?

If the rear diff was never apart, it should be on one of the studs that
bolt the pumpkin into the housing. They're usually on the left side of the
pumpkin.

--
Mike
'90 F-150
'67 Shelby GT 500 wannabe
Ponyboy's Garage- '64 1/2-'68 Mustang parts
home.earthlink.net/~ponyboy428/
I'm always looking for '67-8 Shelby and Mustang fastback specific parts.
Also 428 CJ specific parts, let me know what you have.



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