Re: C4(s) Automatic - Need help with the vacuum modulator lines!  
Re: Re: C4(s) Automatic - Need help with the vacuum modulator lines! -- Ken Merring Post Reply Top of thread Maverick Message Board
Posted by: Tracy Norris
01/12/2002, 21:25:30

 Ken,

I'm really not sure which, but the C4(s?) on my Mav (from the '73 four-door donor) has a two-port vacuuum modulator valve on it.

The tranny runs fine up through the gears but I have to manually downshift it (otherwise it stays in the highest gear I left it in).

This same tranny ran fine before the swap (and the disconnection of its vacuum lines).

Any help where that "second" vacuum line goes to would be a big help... Should I plug it? Hmmmm I'm trying not to hurt the tranny if I can avoid it.

Thanks,
Tracy

Tracey, I think in your question, you have the C4S and C4 switched.
..The C4S does not use a vacuum modulator. These are manuel conrolled transmissions that are the same as a C4 but have a manuel internal valve body.
..The C4 can use either a single or a double port modulator depending on the year and if there were emmission controls involved.
..On the single port, just go to mainifold vacuum.
..On the two port, one line goes to the manifold vacuum, the other would go to a vacuum gating valve that is part of an emmissions system I don't think you have so no place to go with one of the lines.
..If you change to a single port modulator and plumb to manifold vacuum, the trans should shift ok.


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