C6 Transmission Identification

If it's mechanical, electrical or just downright confusing, this is the place to find and share answers.
XR7--428
Registered Member
Posts: 126
Joined: 01 Oct 2019, 18:56
Location: Dallas, TX

C6 Transmission Identification

#1

Post by XR7--428 »

Is there a way to tell what vehicle a C6 transmission came from without removing it from the car? I know they stamped the VIN on the top and I can't access that. Are there any other markings, date codes, stampings, castings that I can get to to tell? If so where are they?

The transmission tag is not there either. Also is there a way to know what line of vehicles a particular servo came in?

I've seen conflicting info on this, so I'm not sure, but will an R servo work in any C6? Could someone not change the servo itself and just replace the cover with one that has an R on it?

The only thing I can see on the C6 that I'm looking are the following. D servo with FOMOCO and a part number that looks to be A-C6AP-70027-A, a raised circle with a 3, a small O and a diamond with what looks like a Walmart star in it. Other side has some letters and numbers. Looks like FCBAP 7006D.

I'll post some pics.
c6-1.JPG
c6-1.JPG (67.04 KiB) Viewed 214 times
C6-2.JPG
C6-2.JPG (61.38 KiB) Viewed 214 times
C6-3.JPG
C6-3.JPG (44.7 KiB) Viewed 214 times
C6-4.JPG
C6-4.JPG (77.57 KiB) Viewed 214 times
Last edited by XR7--428 on 22 May 2020, 15:06, edited 1 time in total.
1969 XR-7 428 Ram Air C-6

User avatar
Royce
Registered Member
Posts: 2514
Joined: 22 Oct 2011, 07:14
Location: Tulsa OK

Re: C6 Transmission Identification

#2

Post by Royce »

D servo would indicate a low performance application. C6AP sounds like a 1966 or 1967 case. The case was made differently beginning with 1968 model year. The 1968 - later cases have a C8AP casting number.

The case can be machined to accept an R servo but will not accept one without modification by a skilled machinist.

XR7--428 wrote:
22 May 2020, 14:35
Is there a way to tell what vehicle a C6 transmission came from without removing it from the car? I know they stamped the VIN on the top and I can't access that. Are there any other markings, date codes, stampings, castings that I can get to to tell? If so where are they?

The transmission tag is not there either. Also is there a way to know what line of vehicles a particular servo came in?

I've seen conflicting info on this, so I'm not sure, but will an R servo work in any C6? Could someone not change the servo itself and just replace the cover with one that has an R on it?

The only thing I can see on the C6 that I'm looking are the following. D servo with FOMOCO and a part number that looks to be A-C6AP-70027-A, a raised circle with a 3, a small O and a diamond with what looks like a Walmart star in it. Other side has some letters and numbers. Looks like FCBAP 7006D.

I'll post some pics.
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
XR7-G Registrar

XR7--428
Registered Member
Posts: 126
Joined: 01 Oct 2019, 18:56
Location: Dallas, TX

Re: C6 Transmission Identification

#3

Post by XR7--428 »

Is there a way to distinguish a 66 or 7 case from the later ones other than the C8AP? I guess it could be an 8. Sometimes hard to tell between a 6 and an 8.
Can you put an R servo cover over any of the other servos? Swap out a D for an R?
1969 XR-7 428 Ram Air C-6

User avatar
Royce
Registered Member
Posts: 2514
Joined: 22 Oct 2011, 07:14
Location: Tulsa OK

Re: C6 Transmission Identification

#4

Post by Royce »

It looks like C8AP in your pictures. You may be able to install an R servo. Be aware the R servo required a different apply lever too.

XR7--428 wrote:
22 May 2020, 15:27
Is there a way to distinguish a 66 or 7 case from the later ones other than the C8AP? I guess it could be an 8. Sometimes hard to tell between a 6 and an 8.
Can you put an R servo cover over any of the other servos? Swap out a D for an R?
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
XR7-G Registrar

XR7--428
Registered Member
Posts: 126
Joined: 01 Oct 2019, 18:56
Location: Dallas, TX

Re: C6 Transmission Identification

#5

Post by XR7--428 »

Royce wrote:
22 May 2020, 19:49
It looks like C8AP in your pictures. You may be able to install an R servo. Be aware the R servo required a different apply lever too.

XR7--428 wrote:
22 May 2020, 15:27
Is there a way to distinguish a 66 or 7 case from the later ones other than the C8AP? I guess it could be an 8. Sometimes hard to tell between a 6 and an 8.
Can you put an R servo cover over any of the other servos? Swap out a D for an R?
What about just a cover with R on it without changing t the actual servo or apply lever? Car shifts just fine the way it is.
1969 XR-7 428 Ram Air C-6

XR7--428
Registered Member
Posts: 126
Joined: 01 Oct 2019, 18:56
Location: Dallas, TX

Re: C6 Transmission Identification

#6

Post by XR7--428 »

Done some more research. Apparently the servo covers had the same numbers regardless of what year they were made or which vehicle they were in. In this case C6AP-7D027. Since it's missing the ID tag, the important thing here to ID is what's on the left side. The casting numbers which are RF C8AP-7006-D. This would make it a 68 case being C8. The car is a 69 model, but was built in mid to late 1968. Should it have a C8 or C9 or could have either one to be right?
1969 XR-7 428 Ram Air C-6

Bluestuff
Registered Member
Posts: 208
Joined: 04 Nov 2018, 01:11
Location: NewZealand

Re: C6 Transmission Identification

#7

Post by Bluestuff »

Just curious,

when was the first application for the C6 trans ?
And what was the “ ridge back “ version on ?

User avatar
Royce
Registered Member
Posts: 2514
Joined: 22 Oct 2011, 07:14
Location: Tulsa OK

Re: C6 Transmission Identification

#8

Post by Royce »

The C8 case was used at least through 1970, perhaps longer. There should be a VIN stamped on top of the case at the rear.

XR7--428 wrote:
23 May 2020, 11:20
Done some more research. Apparently the servo covers had the same numbers regardless of what year they were made or which vehicle they were in. In this case C6AP-7D027. Since it's missing the ID tag, the important thing here to ID is what's on the left side. The casting numbers which are RF C8AP-7006-D. This would make it a 68 case being C8. The car is a 69 model, but was built in mid to late 1968. Should it have a C8 or C9 or could have either one to be right?
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
XR7-G Registrar

XR7--428
Registered Member
Posts: 126
Joined: 01 Oct 2019, 18:56
Location: Dallas, TX

Re: C6 Transmission Identification

#9

Post by XR7--428 »

Royce wrote:
23 May 2020, 16:54
The C8 case was used at least through 1970, perhaps longer. There should be a VIN stamped on top of the case at the rear.
Can you see the VIN stamp with the trans in the car?
1969 XR-7 428 Ram Air C-6

User avatar
Royce
Registered Member
Posts: 2514
Joined: 22 Oct 2011, 07:14
Location: Tulsa OK

Re: C6 Transmission Identification

#10

Post by Royce »

It's possible to see it either with a borescope or using a mirror and taking a flash photo of the mirror. It appears to be the right case for 68 - 70 but the servo never would have come in a Cougar originally.

XR7--428 wrote:
23 May 2020, 18:11
Royce wrote:
23 May 2020, 16:54
The C8 case was used at least through 1970, perhaps longer. There should be a VIN stamped on top of the case at the rear.
Can you see the VIN stamp with the trans in the car?
1968 GT-E XR-7 W code 427 Augusta Green / Saddle
1968 XR-7 R code 428CJ Ram Air Red / Black
1910 Model T Ford Touring Red / Black
1914 Model T Touring Maroon / Black
1915 Model T Ford Touring Black / Black
1917 Model T Ford Torpedo Runabout Green / Black
XR7-G Registrar

Post Reply