I have a 71 Dart with a 225 slant six on a a904 transmission. the kickdown is not hooked up. I dont know a lot about transmissions so here's my problem. I will be driving down hill at 45 mph and the car will shift into third. but when it flattens out and i give it a little gas it will shift back to second. It will also slip into second at 20 mph where normally it will shift at 26-27; once and a while it will shift into neutral and back at that speed. I replaced the fluid and filter, and that fixed it for about 1000 miles, But now its doing it again. Im worried im going to need to rebuild it or something.

First thing to do is get the throttle pressure linkage hooked up and adjusted properly. These are not "kick down" linkages, they perform a vital function for proper transmission operation. Then you can start to determine if you do have a problem.

_________________
Mattelderca
78 NYB (gone now), two S series, three old Snow Cruisers and a Doo.

The transmission throttle pressure linkage is the transmission's only form of load sensing. It's not a kickdown linkage like a transmission with a vacuum modulator for load sensing. Line pressure and shift points are both affected by throttle pressure. With inadequate line pressure the clutch and band apply pressure will be low. If the apply pressure falls low enough the clutches and bands will slip leading to early transmission death. With low throttle pressure the transmission will up shift too soon. With high throttle pressure the transmission will shift late and hard; it will also downshift prematurely.

The valve body is a hydraulic computer. Without that throttle pressure linkage you have removed a vital input to the computer and your transmission will suffer.

_________________
Joshua

Ok i guess i will hook that back up. Does anyone know how to go at that with a Holley 390 with the throttle plate on the left side of the vehicle? Is full throttle where the linkage is all the way back or fowared?

Full throttle pushes the trans lever rearward.

_________________
Joshua