Hopefully someone can help me out, I have a 77 c4 case filled green stripe modulator and what its doing is... I can put it in park, neutral, reverse and drive and it does just fine but when I put it in drive its stuck in low gear(1st) and doesn't shift and it wont shift manually from 1st to 2nd to drive just stays in that low gear(1st) I been told to check governor and vacuum modulator and the psi on it I put a new modulator in it and I have it running to a vacuum tree on my intake and the valves in the governor move freely what else I can check out? Thanks!
Make sure the pushrod was installed from the old one to the new one. I've seen cases before where this part was forgotten!
Are you saying the pushrod needle on the vacuum modulator? I haven't checked that yet.... I'll take a look at it.... when I take the modulator out how would i know if its in the right way or if its wrong?
it's more of a...is it in there or not. I have used finishing nails cut to length to make them...longer/shorter...
that would work... never would have thought of that but I'll check to see if its in there I dont remember paying that much attention when i put the new one in awhile back but I have read that they can be put in wrong and forced in.
Here's a decent article about it: http://www.fordmuscleforums.com/c4-transmissions/506330-modulator-rod-lenght-convertor.html
so i took my vb apart and there was a lil almost flat piece of metal fell out and I have no clue where it goes I would post a pic of what it looks like but my pics are in my gallery and i dont know how to post it i dont have a url for the pics?
I don't see any pictures in your Gallery on this site. The URL can be copied from "Properties" after you right-click the picture, as long as it's on a website somewhere and not on your local computer. Have you removed the modulator to see if the pushrod is there yet?
Hey Paul, hey I took the pics personally so they are not on a website, I couldn't find anywhere online of a pic of the piece im talking about. and not yet I haven't had time but ill check here in a lil and post back. When I pull the modulator out will the push rod come out with it if i have one or do i need to stick a magnet in the hole to get it out?
This piece... \ The only thing I can think of is the spring-retaining pin (305043) which is listed as 1/16" x 11/16", but I'm not sure if they are flat or round. It's been a while since I had a C4 apart... Just a stab in the dark.
The push rod usually comes out with the modulator. Also check to make sure the throttle valve is installed the correct way. The pin pushes against it and the pin should sit into the dimple on the end of the throttle valve.
Thanks for the diagrams, sorry just got home from seeing the wife's family in Alabama...And yes that's the pic I was talking about...I went out and checked the valve body and my valve body was slightly different from the one in the diagram you posted but I checked to see if there was anywhere on the VB that a flat pin would be missing or may looked like it would go and didn't see anything... I'll try and post a pic of my VB when I can...I'm about to go out and check the push rod in the modulator in a min and I'll post back, and thanks a lot for all this help hopefully we will figure this out.
