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Technical => Transmission Swaps => Topic started by: jhicks5 on 2022-05-23 11:25

Title: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: jhicks5 on 2022-05-23 11:25
I replaced the 3.03 3-speed in my 57 Ranchero with a Fordomatic.  Pretty sure the new one is from a 1957 as well and I am going to check the serial numbers.  It has coolant lines to the radiator, and functions like a proper 1957 Fordo; a 2 speed + the Lo 3rd gear.

When I re-assembled I used the same speedo cable and gear (from the 3.03 3-speed) and the speedometer does not work.  I suspect that the driven gear is not engaging with the drive gear mounted on the tailshaft of the Fordo.

I have called a couple of the parts houses and am not getting to a solution. They show what I would call a "T Shaped" driven gear through 1956, and then a more cylindrical shaped gear starting in 1957. My car has the later cylindrical style, which is also the style I have seen in 1958 Cruisomatic and I think later C4s etc. Seemingly this gear should work, but does not.

Any guidance on what I should be looking for on a Fordomatic from 1957?
Thanks
Jim



Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: gasman826 on 2022-05-23 18:20
Are you dealing with the long gears?
Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: KULTULZ on 2022-05-23 18:26
QuotePretty sure the new one is from a 1957 as well and I am going to check the serial numbers.

Can you supply the TRANS ID NO to be sure of what you have?
Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: jhicks5 on 2022-05-24 08:01
The tag on the side just above the tranny pan on left is 161236.  This does not seem like a Fordomatic number based on what I have seen.  Also looked on the case and found nothing - should be something in this format I think PXX-7006-X but can't find it.

Gasman - Not sure what you mean by "dealing with the long gears"

Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: gasman826 on 2022-05-24 08:26
Long speedo gear rather than the common short gear.
Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: jhicks5 on 2022-05-24 10:22
I am familiar with two types of driven gears (sample images attached) the "barrel" shaped one below which I have called 17271 and the "Tee" shaped one which I have called 17322. I am not positive the two separate types are identified by these base numbers but it seems logical. The "long gear" image you sent does not look like either, but would appear to have possible interchange with the barrel shape. I have worked with Ford automatics vintage 1957 to the late 70s and have always used the "barrel" shaped one, and attributed the "tee" shape to the earlier 1951-1956 Fordomatic.  I am looking at the Ford '49-59 parts manual and both base numbers are used on 1957 Ford with Fordomatic, depending upon 1) rear end ratio and 2) tire size. For example, my car has a 3.56 and equipped with 7.50x14 tire requires B7A 17322-R, while 6.70x15 tire requires COAA 17271 G. This suggests either of the two gear types may be compatible on the 1957 Fordo.

After consulting the Ford parts book and a friend who has torn apart hundreds of '57s, it is the "barrel" style that I need, as he did not even know about the "tee" shape gear. Further, the parts book says the speedo cable core length for a 3 speed is 55.80" while for an automatic is longer, about 59" I will be looking for a longer cable compatible with the barrel gear.

So, I guess I am not really looking for the "long gear" unless I am missing something here. 
Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: KULTULZ on 2022-05-25 04:01
Quote from: jhicks5 on 2022-05-24 08:01The tag on the side just above the tranny pan on left is 161236.  This does not seem like a Fordomatic number based on what I have seen.  Also looked on the case and found nothing - should be something in this format I think PXX-7006-X but can't find it.

Sounds like it was rebuilt at one time and the re-builder attached his ID and removed the FORD PLATE.

Don't you love it?  :002:
Title: Re: Correct Speedo driven gear and cable - conversion of 3 speed to Fordomatic
Post by: jhicks5 on 2022-06-06 19:33
It was a bad cable.  Found a good used one, cleaned and lubed it. The gear was the barrel style and the 22 tooth gear that was in it was the right one.  Speedo is off by maybe 1-2 mph at 40 mph. Good to go.  Thanks