Technical Ford C-4 no downshift

I put a used C-4 in my sunliner and has been a fight to get it to shift right,go on a highway drive and no down shift after getting off the highway but would have to manually shift it for a couple miles then it would start shifting on its own. Took it on a long cruise a couple weekends ago and got it good and hot so it started acting normal but today when leaving a show it did a very long delayed shift into second then full manual,was thinking it was a sticking governor but could the governor stick completely and go full manual shift or something in the valve body.

 

The Ford governor has two weights/valves. The small one actually controls governor pressure as speed goes up and down. The big one prevents any governor pressure until you get to 5 -10 mph. It also dumps governor pressure as you coast down into this mph range. If it sticks in, you get a really delayed upshift or no upshift at all. This was common in Ford products with a C-4 or a C-6 in very cold weather. If it sticks out, it may stay in high or second gear after the vehicle stops.

With that said you could have either a governor problem or a valve body problem. I'd bet on the governor, but the valve body is easier to get out since you only have to drop the pan. You can also get an idea of the transmission's condition by what is in the pan. Back in the 70's I cleaned a lot of C-4 valve bodies on fairly new cars. However, if you find the valve body varnished up with sticky valves, you had better remove and clean the governor.

 

I had a governor cause that in a C6 years ago.

 

Took it on another drive and it started to shift normally,if it was in anything other then my convertible I would have that tail shaft off but the convertible frame has a big X in it that might make taking the tail shaft off impossible. I had the pan off to replace the shifter arm and it was not too bad but what can make the governor stick.

 

Check the vacuum modulator. You should also stop buying junkyard rejects and learn to fix what you already have; I rebuilt a C-4 transmission when I was a teenager and it actually worked when I put it back in the car. If I can do it you can do it.

 

Dirt, burned fluid or the fact that they sometimes stick. The C-4 doesn't have much of a filter, it's just a screen.

 

I think the trans sat for some time.

 

Was thinking about trying to fix the governor while still in the car so I took a parts trans apart and no way,since I am planning on going back to a Y block and most likely going to use a C-4 behind the Y the adapter requires a case filled and all I have are pan filled. Located a case filled and will have it gone through and will not have to change trans when the Y block is ready to go in.

 

I found a burr in the valve body on the 1-2 portion of the valve body, while installing a shift kit. My trans did the same thing you are describing when cold, and the issue went away at full operating temp. might be worth pulling the valve body and checking everything over.

 

As stated earlier , I would check the vacuum to the modulator at the intake and down below.

 

The vacumn was one of the first things I checked after installing the trans after I found it did not want to shift right and has a new modulator valve.

 

How long did it sit up? It may just need to be driven. Although I concur with the recommendation to pull the pan.

 

Do not know jow long it sat but it got pulled to put in a T-5 so there must have been a reason.

 

Time to get a fresh trans,tired of wasting time on this one.