I have a 1978 f250 with a c6 and a 460 4x4 I rebuilt it and put a transgo shift kit in it. Now It doesn't like to downshift from 3 to 1 at a stop. I can improve it with the modulators but that hasn't fixed it yet I took the governor out and cleaned it up that didn't help. If I unhook the vacuum from the modulator the problem is fixed. I was wondering if I could change the modulator to improve this or the modulator rod and if so what would I want to go with? I set the modulator the way the shift kit directions said with their rod but It seems if I adjust the modulator screw clockwise, the problem gets worse and counterclockwise improves the issue. Do I need a longer rod and a stiffer modulator or am I doomed to a new valve body. Does this make sense to anyone? Also, how does a C6 governor woek? I know as it turns it slides over and moves a valve, but how does the primary side work where the spring holds the valve against the side? Does the fluid shove the valve over then when the shaft spins does it open or close or what? I was a little stumped. Thanks.

 

Well I didn't get any help here on this but it lookslike this has been a problem for some others. The general consensis is that the governor is stuck. That is what the 2 tranny shops said and the guy from transgo who I bought the shift kit from. I fixed the problem by tightening the screw in the modulator. I think the line pressure was low enough that it wasn't pushing the governor against the spring and was staying in high gear. With a boosted line pressure, it shifts flawlessly. I hope I can help someone.