Need help with speedo driven gear

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Mar 1, 2013 | 09:03 PM

JMV in PA

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Joined: Mar 2013

Posts: 7

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From: Atlas, PA

Need help with speedo driven gear

First off I am new here so if something is posted wrong please let me know.

Now for my issue:

We (I say "We" because this is a family venture) are looking for the correct driven gear for my 85 F350 2wd Dually Dump body. This truck is a pile of parts from different F series trucks. The speedo never worked since we owned it. We were never worried about it until now. We are now looking into it because the old T-18 decided to puke and we replaced it with a T-19. We found the drive gear in the T-18 was worn smooth in the center (not sure why) and don't want the same thing to happen in the T-19 which has a good drive gear.

Here are the specs:
Chassis: 85 F350
Cab: 83 F150
Engine: 460 ci
Trans: T-19 with yellow 7 tooth drive gear
Rear: Looks like Dana 70/70U Dually with 4.10 gears (gears determined using the rotate tire and count drive shaft revs.)
Tire size: 225/75/16 (not original size - dad got these tires cheap)
Tire diameter: 29.3 inches (using miata.net tire calculator)
Current driven gear: 18 tooth, brownish in color, only mark on it is a "2"

If any more info is needed please let me know and I will try to get it. If I can figure out how, I could post pictures if needed.

Thanks in advance for the help.

Mar 2, 2013 | 08:50 AM

vwbill

Freshman User

Joined: Feb 2010

Posts: 39

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From: Casa Grande

Need help with speedo driven gear

TCI Ford Speedometer Gears - JEGS

This link has the formulas you need to convert tire dia to speedo teeth. Once you know tooth count you want, I think there is more available than what is on that page.
William

Last edited by ctubutis; Mar 2, 2013 at 10:05 AM. Reason: remove bold, please use that only for emphasis as needed else it's considered shouting

Mar 2, 2013 | 07:46 PM

JMV in PA

Thread Starter

New User

Joined: Mar 2013

Posts: 7

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From: Atlas, PA

Need help with speedo driven gear

Thanks for that web link. It was exactly what I needed.

One more question:

I believe me current driven gear is a type 2 based on comparisons to pictures I have found on the web.

Is a type 2 driven gear the correct one for a T19 tranny or do I need some other type.

Thanks again.

Mar 2, 2013 | 08:18 PM

ctubutis

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Joined: Nov 2007

Posts: 22,415

Likes: 92

From: Denver Metro Area, CO

Any Ford speedometer gear will fit and work in any Ford transmission.

Mar 2, 2013 | 09:39 PM

81ChopTop

Laughing Gas

Joined: Nov 2011

Posts: 1,033

Likes: 11

From: Wausau, WI

Quote:

Originally Posted by ctubutis

Any Ford speedometer gear will fit and work in any Ford transmission.

I said basically the same thing a while back and got flamed for it, don't know why.
I've switched so many speedo gears out of so many different trannies and have never had any problems.

Mar 2, 2013 | 09:52 PM

ctubutis

Moderator

Joined: Nov 2007

Posts: 22,415

Likes: 92

From: Denver Metro Area, CO

Quote:

Originally Posted by 81ChopTop

I said basically the same thing a while back and got flamed for it, don't know why.

Where is that Tim Taylor thing.....

Ah ha! Good ol' Google...

Dunno why you got flamed? Shouldn't have been from me, right?

These type places can be filled with lots of chest beating & swingin' dicks trying to show off, though....