Speedometer gears

[Doug Comer]

Need to find the drive gear( the one in the transmission) for my 1967 F100 4x4. Has 3.54 ratio. From what I can figure from the chart I need C3OZ-17285-C which is a 7 tooth. Anyone know where to get this? I looked a little but got frustrated so I thought I would ask for help.

Doug

[70_F100]

Doug, need a little more info.

What size tires (diameter)?
What transmission and transfer case do you have? Since it's probably a Dana 21 transfer case, is the speedometer driven off the transmission or the transfer case?

Given that info, I may be able to help.

[Doug Comer]

I have 235-75-15 which comes out to 29-30 inches. NP435 with the dana 21. And from near as I can tell it it is driven from the transmission. I found another gear in my bone yard but guess I should verify that its right before going to the trouble to put it in. Thanks for the help.

Doug

[70_F100]

Doug, it appears you're right on the 7-tooth drive gear.

The calculator I used came up with a 7-tooth drive gear and 17-tooth driven gear. The Ford MPC lists C3OZ 17285-C and C3DZ 17271-B for that combination in your truck.

You might want to try your local Ford dealer first (MAY still be available) or Green Sales, but here's what I found:

C3OZ 17285-C
Mustangs Etc
Van Nuys, CA 91411
2 in stock

Perogie Enterprises
HIGHSTOWN, NJ 08520
609-448-1684
1 in stock

C3DZ 17271-B
No Ford dealer or obsolete parts vendor has any in stock.

Hope this helps!!!

[Doug Comer]

Thanks very much. I will try that and see what I come up with.

Doug

[Doug Comer]

I think I messed up. I pulled it apart to install the new old gear I found. I was fighting the snap ring that retains the gear and ended up pulling the output shaft out. Now do I need to drop the whole trans and line everything back up (this is what I think) or can I do it through the side cover?

Thanks
Doug

[70_F100]

OUCH!!!

You can pull the top cover and see if the pocket bearing is still in place (it's the one in the rear of the input shaft that the mainshaft slips into), and if so, you may be able to work it all back in.

Did the shaft itself come out, or did the bearing and gears just move backwards far enough that the bearing came out of the rear of the case?

[Doug Comer]

From what I can tell the bearing and shaft moved towards the rear far enough that the bearing you see with the tail housing remove came out of the case. Will probably head back out to the garage tonight as now this rig is my daily driver

Doug

[Doug Comer]

Ended up pulling the transmission out and putting it back together. Everything works good. Speedo is a little jumpy above 50mph, but I'm pretty sure it just needs a little lube. Thanks for the help.

Doug