need correct speedometer gears

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Jul 28, 2025 | 10:32 AM

Goshencars

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Mountain Pass

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need correct speedometer gears

I need to change the speedometer gears in my 50 f2 4 speed crash box. I am installing a newer rear end with a 3.73 ratio to replace my old 4.86. the old driver gear is 20 tooth # 01Y-71 C-20. The driven is DY-85-A8. I am going to run 7:00-16 tires with an OD of 30.6" diameter.What gears do I need and does anyone have a set? Thanks

Jul 28, 2025 | 11:13 AM

bmoran4

Parts Nerd Extraordinaire

Joined: Sep 2010

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From: Western NY

Your 4.86, 7x16, and 4 speed would have a 01Y-17285-A 6 tooth gear and 01Y-17271-C 20 tooth gear. The

-17285-A was for the 3 speed...

I'm not finding that Ford has a prescribed matching combination listed for 3.73, 7x16, and 4 speed.

Jul 28, 2025 | 12:23 PM

Goshencars

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Mountain Pass

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I also thought of putting an external speed change unit on but while it is apart it would be nice to switch the gears.

Jul 29, 2025 | 09:55 AM

Jeeptrix

Tuned

Joined: Sep 2007

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From: Langley, BC

If you figure out the correct gear required Chuck's Trucks is the first place to look for it.

Jul 29, 2025 | 10:23 AM

Goshencars

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Mountain Pass

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Jim Carter trucks lists a changer for $160 for GM. Is Ford and GM interchangable on their cables?

Jul 30, 2025 | 07:39 AM

Goshencars

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Mountain Pass

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I found an old thread (2015) that had a similar request. They listed the following gear set. drive gear 8J 17285 and driven gear 01T 17271-A. Will these work to get close and does anyone have them Thanks