Cospanky

Hello Mustang lovers. I am having a problem with my 1966 Mustang green screw in moderator C-4 tranny, it won't go into 3rd gear. I have checked the vacuum to the moderator which was 12lbs, i have removed and checked the spool valves, I have tried starting in 1st, shifting to 2nd, then to 3rd, I have taken it up over 75 MPH and none of this works. I had all new clutches replaced and still nothing. Can anyone help me?? Thank you..

ThetaTau87

I had a C4 that was shifting odd for years until I removed the pan to fix a leak and change the filter. I discovered that the ball for the check valve was missing and not controlling the fluid flow like it should. I replaced the ball and it shifter great ever since.

Cospanky

I have not tried that one yet but will Theta. Thanks for the info.

Cospanky

Hello Mustang Fans.
I am having a problem with my 1966 Mustang C-4 transmission it won't go into 3rd gear. I have checked the vacuum to the moderator which was 12lbs, I have removed and checked the spool valves, I have tried starting in 1st, shifting to 2nd, then to 3rd, I have taken it up over 75 MPH and none of this works. I've replaced the white moderator and had all new clutches replaced and still nothing. Can anyone help me?? Thank you..

jlg2002

Have you checked that your intermediate servo is working?