I went ahead and ordered a kit of 5 driven gears so that I can use whichever one is most accurate. Using the information above, I believe I will need one with 17 teeth.


Thanks for posting that list. I appreciate the help!

 

Here's the part numbers/tooth count/pics of the DRIVEN gears (TYPES 1, 2, 2A). You do not want TYPE 2B (C2DZ-17271-J), because the teeth run in the opposite direction.

Post #9: I said the rear axle ratio was required. Usually when I say this, people just list it. The DRIVE gear info isn't required, because w/a C6, it has nothing to do with it!

Upper pic: Part numbers/tooth counts // Lower pic shows the types.

 

Can we run this again for a 4.10 gear ratio?

 

Well this has me thoroughly confused. I have a 1982 F100, I believe C6 with 3.25 axle ratio. I just got new tires (Cooper Evolution H/T 265/75r15) that are 30.5 inches tall and 680 revolutions per mile. My math came out to a driven gear of 15.45 (need to round up/down), did I do that right? (I used a Drive gear number of 7, but I dont know if that's correct either)

 

I just ran into the same thing on my 62 f100. I had a c6 rebuilt. It's not original to the truck. I put a 65 or 66 f100 rearend behind it with 3.25 gears. It's not original to my truck. Looking for information on what bullet/ transducer goes between the speedometer cable and the transmission. Any help would be welcomed. Ty

 

I was able to get this figured out on Gary's site. Here's a link: https://www.garysgaragemahal.com/spe...--sensors.html

 

I should add, that I got the gear off amazon for like $12. I did a quick search and they still have them with various gear teeth available.

 

Ty dogwood, I need the whole piece that the gear fits into. I heard the cable screws into the end and then I heard it's crimped on. I have no idea what year the c6 I have is and no numbers.

 

This it? https://www.ebay.com/itm/233752040091

 

Might be. I've been told that there are 2 different kinds that attatch to the speedometer cable. I need to figure out the gear on that as well

 

Normally, I would not disagree with you Mr. Wilson, (NumberDummy), but you are incorrect, there ARE more than one tooth count output shaft for the C6, the ones I have seen are: 6/8/9 Tooth drive gears ground into the output shaft of the C6. - You cannot get the speedometer gearing correct UNLESS you know which one you have!

I have physically seen and experienced the differences. I have found 6T drive gears in Econoline Vans with 4.10 gears that had 17T Driven Gear. - I swapped this trans for one in E150 with 2.75:1 Axle Ratio, and had to use a gearbox to change the speedometer reading because there is no 12T Driven gear to give me proper 1000 RPM, for the speedometer. - Please see below!

E150 C6 2.75:1 Axle x 720 Rev Per Mile Tire = 2000 Driveshaft Speed
With a 2000 RPM Driveshaft Speed (@60) you need a 2:1 reduction to get 1000RPM at the cable to drive the speedometer. 18T Driven and 9T Drive Needed

E350 C6 4.10 Axle x 680 Rev Per Mile Tire = 2800 Driveshaft Speed
With 2800 RPM Driveshaft Speed (@60) you need a 2.8:1 reduction to get 1000RPM at the cable to drive the speedometer. 17T Driven and 6T Drive Needed

I have even seen different combos listed in the book for different tire sizes and same ratio.

trans code - Trans - engine - Cyls - Output shaft gear teeth
PGD-AA3, 4, 5 C6 351 8 1978 E100 — 8 tooth speedo. drive gear
PGD-AC4, 5 C6 351 8 1978 E150 — 9 tooth speedo. drive gear
PGD-AC6 C6 351 8 1978 E150 — 9 tooth speedo. drive gear
PGD-AF, 1, 2 C6 351 8 1978 E250 — 6 tooth speedo. drive gear

This image if it loads, is clipped from the 80/89 Ford Truck MPC please see there are part numbers for each 6/8/9 Tooth Gear on the output shaft.