C4 trans question...

Discussion in 'Mustang II' started by cobraii351, May 4, 2004.

  1. cobraii351 Founding Member

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    Are the govener springs in the C4's different for different rear ratios? With a lower ratio rear the drive shaft would spin faster and the gov. would kick in faster. My trans shifts way too quick for my liking and I was wandering if I could change the springs or the entire gov., And would this make a difference in the shifting in drive at part throttle. ( I have no Kickdown)

    Thanks,

    TIm
  2. Project 77 Founding Member

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    Tim.

    Doesn't your C4 have a module on the tranmission? I have one that a hose goes into, and if you remove the hose there's a screw you can turn to adjust shift points. I had to adjust mine because it would wind out way to far, and I don't have a Kick down either.
  3. cobraii351 Founding Member

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    Yes, it does but you can only adjust it so far. I was just wandering if I put heavier spring in the gov. if that would make a difference as well. I get really short shifts in drive when the pedal isn't on the floor. 20mph and is it 3rd gear already. I don't evern make it accross an intersection before it's in 3rd.

    Thanks,

    Tim
  4. Blue Thunder Active Member

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    I don't specialize in transmissions, (except for blowing them up) but I don't think C-4s have any gov springs at all. (that's GM's thing)
    As far as I know, shift points on the C-4 are entirely controlled by the vacuum modulator. I had a 1968 police duty C-4 in my Stang years ago, and it had an adjustable modulator, which I messed with, of course. The car would shift early if I was lightly on the throttle, but under full throttle, the trans would shift at 6500 RPM. It was a nice setup for the street. Very consistent.
  5. Blue Thunder Active Member

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    You can always test and see where your Trans shifts with the modulator hose unplugged from the back of the intake.
    My guess is, you need a new adjustable modulator, because yours isnt functioning correctly. (that is, assuming you've turned the screw inside the vacuum nipple on the modulator, and it's still not shifting higher)
  6. cobraii351 Founding Member

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    No, there actually is a gov. inside the tailshaft housing. It is part of the output shaft. The are some small weights and spring to overcome them at low speed but as the shaft speed increases the centrifical force is supposed to overcome the spring and the gov. does it's thing. But I might have a crappy modulator, good point. I'll have to try changing it out when it comes back for the body shop.

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