I'm trying to find some information ( thread ) on the ford transmission identification. I done a search on here but I couldn't get anything to pull up. The pan has 17 bolts which should be a C6 but the tail shaft is stubby and only 8" from the back of the pan to the end of the housing. The speedometer cable goes in on the passenger side rear, and it just screws on, instead of having the plastic gear that goes in, with the bracket for the bolt that would hold it in. Where I have changed my rear end gear, my speedometer is now way off and I was wanting to change the speedometer cable gear to correct my speedometer. I'm also going to replace the complete speedometer cable , but I'm trying to make sure of what exact transmission I have. Any help or information will be greatly appreciated. Thanks !

 

this is what the back of the transmission looks like and where my speed odometer cable goes in

 

I think these are the casting numbers -D2TP-7006AA And on the passenger side in front of were the speedometer cable goes in it has these numbers - RF G8TR
7A040A
W1----? Thanks !

 

I'm thinking 1972 C6 from a F600 or so. Those tended to have a rotation reducer mounted on the back of the speedometer.
I *might* have one laying about.
I'll take a look tomorrow.

 

Okay thanks. It will be great if I can figure out exactly what I have. I have changed the plastic gear with the little clip on the speedometer cable before,but I've never done this type were the little inner cable goes in about an 1/2 inch and the threaded cap nut holds it on. Thanks !

 

No such thing as G8TR

 

On the picture, you can see this G8TR on the passenger side and D0TZ-17260-E is on the drivers side of the transmission.

 

On a ford transmission forum I gave them this information, and I was told the following information -- That this transmission was a C6 that came out in a 1972 with long wheelbase, with a two piece driveshaft with a center support carrier bearing. So who ever installed this transmission in this truck before I bought it, also used the two piece driveshaft with the center bearing/support. By looking at this picture I put on here can anyone tell me what I need to do to change the speedometer gear to get my speedometer to at least be within 5 mph of being correct ? Right now with the rear gear change it's 15 mph off. When I removed cap nut that holds the speedometer cable in, there's not a plastic gear on the cable, but just the inner cable sticking out about an 1/2 inch. Is the gear that has to be changed inside the transmission housing ? And how do I change it ? Thanks for any help !

 

C8 = 1968 / G8 doesn't exist, because this would be 2008 if it did.

D0TZ-17260-E is a speedometer cable. Ford part numbers are not marked on parts after 1956, and no trans case would have any reference to a speedo cable.

1967/72 F100/250's w/a 131" wheelbase came with a two piece driveshaft w/a center support.

You failed to mention what you're working on, but if this is an F100 or F250 2WD w/a 360 or 390, the only A/T would be the C6.

D2 = 1972. The nylon speedometer DRIVEN gear at the end of the cable could have 16 thru 21 teeth. These are available from Ford & auto parts stores.

 

Sorry about the numbers, I had a speedometer cable pt number laying here. The numbers on the drivers side of this transmission are - D2TP-7006AA , and the other set of numbers of RF G8TR 7A040A are on the passenger side of this transmission right in front of were the speedometer cable mounts and is easily seen in the picture I posted. The truck is a 1967 F100 ,short wheelbase,390 engine. It originally came out with a manual transmission. Before I bought the truck someone had changed it over to an automatic, and the guy I bought it from said all he knew was that the transmission was a C6. The speedometer cable on it is not the type that has the plastic gear with the metal clip and the little metal mounting bracket. You can see in the picture the speedometer cable going into the transmission, and when I removed the cap nut to remove the cable there is NO gear attached to it, only the inner cable sticking out about an 1/2 inch. I'm just trying to figure out how to change the speedometer gear on this type. I have changed the other type before with the plastic gear like you mention. Thanks

 

Looks like you undo the speedo cable, and then unscrew that nut (17269) to get to the shank of the drive gear (17322)

.http://www.fordification.com/tech/images/c6_03.jpg

If your trans still has its metal ID tag, here is a list of probable trans applications:

Ford Truck Automatic Transmission Application Chart '64-'72 - FORDification.com

 

Someone also swapped in the 390, because the only V8 available in 1967 F100/350: 352 2V .. 360/390 introduced in 1968 (as was the C6), used thru 1976.

There were TWO different DRIVEN gears used with 1968/72 C6: iron & nylon. There's also a steel DRIVE gear on the output shaft if the C6 is from a 1968/72.

If the C6 is from a 1973 and later, the DRIVE gear is made as part of the output shaft, so it cannot be replaced by itself.

What is the axle ratio?

 

When I had my engine rebuilt, my engine man bump everything up to a 390. So I just refure to it as a 390. This speedometer cable is not the type with the nylon gear. I know about the nylon type gears, because I have changed them out before. When I remove the cable there is no gear attached to the end of it,just the inner cable sticking out about an 1/2 inch. Number Dummy, looking at the picture I posted can you tell me how the speedometer gear would get changed in this type ? I changed my rear axle ratio, and that's why I wanting to change my speedometer gear to get my speedometer back close to reading correct.I was wondering if the gear I need to change is under the large nut were the speedometer cable screws on. ( see picture ) Thanks for your help !

 

What is the AXLE ratio? I cannot help you without it.

 

Okay, the truck came out with a 325 gear. When I bought it, I lowered it down some and changed the wheels and tires. When I first got the truck the speedometer was already off about 7 mph. and the rear gear had been changed to a 370 gear by the previous owner. With the new rear wheels ( 29" tall ) that I have on it now , I changed out the rear gear axle ratio to a 255 gear which works great and ended up being right what I wanted .I'm just trying to get my speedometer to at least 5 mph of being correct. right now it's about 14 mph off on the low side. I used my app on my phone to check it and when I was running 70 mph my speedometer was only reading 56 mph. Now at 70 mph I'm turning only 2300 rpm which was what I was wanting. All I'm trying to find out Is how this type of speedometer gear (see picture) changes out ? I know about the nylon gear type and have changed them,but I have never changed this type. Thanks !