I have a pre 1970(c-4) full manual reverse valve body in my car. My issue seems to be with a 2-3 shift. The clutches had excessive clearence so i went into it and freshened it up a little. Assembled it now it has no 2-3 unless you get the line pressure up and it sort of glides in. I removed the valve body, dissassembled it. Found the throttle modulated valve spring broken and the valve to be sticking. i replaced the spring with the closest thing i could find from a trans go shift kit. i got the valve working freely. out it back in. still has an issue. Btw this is supposed to be a fairbanks v.b. I'v had it for ten years or so i bought it second hand.This is my first problem with it. Any ideas? Also one thing that might help if anybody has a beak down on this thing all i can find is 70 up.
In a manual valve body there is no modulator valve or throttle valve. Manual valve bodies use relief pressure to change gears. The relief pressure is usually set high in these valve bodies - 230 to 250 psi. If that is the spring tha was broken and you replaced it with a green or yellow spring from a TransGo kit it should work fine - though it wouldn't hold as much torque as it was advertized to hold because the pressure would be close to 200. When you freshened up the tranny did you put new seals in the clutch pack pistons? Especially in the second clutch pack from the front (the forward gear clutch pack)?
I wont lie no i didnt simply because this this only had a couple hundred miles on it. It worked fine except for the excessive clearence in the direct clutch. i installed new fibers and steels and got the clearences correct and air checked them. Im still not having any luck with it. The 2-3 shift is sloppy at best. My valve body diagram shows the valve behind the 2-3 shift valve to a modulated valve. It doesnt have a modulator valve(externaly) per say. The seperator plate does away with all that. What exactly does the 2-3 cut back valve do? And does this older valve body not operate with the same valve placement as the newer ones?
There are 64-66 and 67-69 valve bodies that are "pre 70. They had different features and operated differently. Was the transmission working with this valve body in it before? I still say either or both of the apply pistons are leaking.
The pre 70s case to valvebody ports are differnt, I tried to put a newer V.B. in a old case, Wouldnt work, maybe your problem?
It's a mathched set both came from a 65 mustang. Now im curious i thought that the newer v.b. would fit my case but mine wouldnt fit in a newer case, because mine has an extra bolt on one side. I fixed my shift issue btw. Either the spring that i replaced didnt seat properly or just the tension fixed it.
cases for the pre-70s and post 70s trannys are different. The valvebodies have different bolt patterns and the cases are ported differently.
