1966 ford mustang c-4 transmission

[1949 PLYMOUTHP17]

we have a c-4 transmission that shifts normal. drives just fine. when we manually downshift to drive 2 nothing happens. it will manually downshift to drive 1. we checked the linkage for proper adjustment. is the problem in the valve body? we didn't even know there was a problem except when we were driving a steep hill and downshifted to drive 2 to make the climb easier. thank you for your help.

[rocketraider]

Trying to recall how those years Cruise-o-Matics worked. I think putting the shifter in the green dot drive position allowed it to run thru all 3 ratios, and in the small white dot drive position it either started in 2nd or wouldn't shift past 2nd. Been 50-plus years. 

 

All I can recommend is fluid and filter service. Others here are well-versed in 60s Ford.

[Oldtech]

Does it have the D1 and D2 ranges?  or D-2-1 ? If it is the D1-D2 setup the only difference is that D1 starts in first and D2 starts in second. 

If it is the D-2-1 and nothing changes there is possibly something sticking in the valve body.  However  if you put it in 2 from a stop it will start in 2 and remain there. 

It is also possible the trans has been changed and isn't the one the shift quadrant says it is.    Seen that!

[Bloo]

Sounds normal for 1966 or earlier to me.

 

Green dot is 1-2-3, located where second would be on a newer Ford.

White dot is 2-3, located where drive would be on a newer Ford.

 

Edited May 7 by Bloo (see edit history)

[Littlestown Mike]

Sounds correct for a '66 C4.  The 2 Drive ranges are as only affect the lowest gear to start out from a dead stop.  D1 shifts thru all 3 speeds, D2 starts in second and then shifts to 3rd, normally.  D2 is used for starting on snow or mud.

To force a downshift from either  D1 or D2, use L.  You may also have to press down on the gas pedal to force the downshift--the governor should prevent from shifting into 1st at too high of a road speed.

I believe the Select Shift ( D, 2, 1) where you could manually select 1st or 2bd came about in 1971 and continued until the end of production.

 

[rocketraider]

Which shift selector do you have?

 

Listed as 65-66:

 

 

 

67-68, but also listed as 66 in some repro parts catalogs:

 

 

[rocketraider]

2 hours ago, Littlestown Mike said:

I believe the Select Shift ( D, 2, 1) where you could manually select 1st or 2bd came about in 1971 and continued until the end of production.

Part of Ford's Select-Shift Cruise-o-Matic advertising was by selecting 2 it "starts in second, stays in second".

 

My late deer-demolished 93 F150 worked like that as does the 02 Grand Marquis. I think the 08 F150 does but I've never tried it!😊

 

At first I thought "what good is that?" but after owning Fords with it I can vouch for it being a useful feature.

[Bloo]

@rocketraider's first pic with the green dot and white dot is what you would expect to see in 1966. If you wanted those labeled "D1" and "D2" instead of Green Dot and White Dot, I think you had to step up and buy a Mercury.

 

D-2-1, as seen in @rocketraider's second pic for a transmission with a manually selectable second gear and would be 67 or later.