Shift points C4 change ? - Ford Muscle Forums : Ford Muscle Cars Tech Forum
 
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post #1 of 13 (permalink) Old 04-22-2007, 02:14 PM Thread Starter
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Shift points C4 change ?

My car a 69 Mustang 302 is tuned it works now with higher revs. The C4 is a 1969 model.
The shift points are low 37 mph and 68 mph. How can i change the shift points to higher mphs ?

I have a hotter cam a competitin cam XE256H-10 , 0.477 0.484 , 256 268, and Duration At 0.05 212 218. The Engine has Holley carb 600cfm, dual exhaust, try headers, maifold dual plane edelbrock and ported heads.

Thanks
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post #2 of 13 (permalink) Old 04-22-2007, 07:52 PM
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Shift points C4 change ?

You can adjust the tranny vacuum modulator....clockwise turn on set screw inside vacuum line connection...

If that does not increase to the desired rpm range, lighten the secondary valve inside the tranny governor...
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post #3 of 13 (permalink) Old 04-23-2007, 11:18 AM Thread Starter
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Shift points C4 change ?

Where is the governor ? Perhaps behind the cardan shaft ??
Yo mean lighten = longer stretching ?
Thank you for the Help.
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post #4 of 13 (permalink) Old 04-23-2007, 10:01 PM
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Shift points C4 change ?

You have to remove the rear housing, it is located, on the output shaft, held on by 4 bolts.....there will be two pistons. the secondary will be the smaller one.....

http://raceabilene.com/kelly/hotrod/...rans/c4exp.gif

governor is part 116a..

review this posting, you may want to buy a spring...
http://www.fordmuscle.com/forums/c4-...ive_56158.html

I recently added this spring, and drilled out my secondary valve, and it will change you full throttle upshifts....my secondary valve initially was 14.9 grams, now it is 13.3, and will auto upshift about 5500rpm...at 12.3 grams, it upshifted about 6100 rpm....

This will also increase your auto downshift speeds....which is also increased, will downshift to first at a much higher speed...now about 37mph...which is great for my car!!

<font size=-1>[ This Message was edited by: markboss on 4/24/07 1:05pm ]</font>

<font size=-1>[ This Message was edited by: markboss on 4/24/07 1:06pm ]</font>
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post #5 of 13 (permalink) Old 04-25-2007, 04:15 PM
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Shift points C4 change ?

The vacuum modulator has nothing to do with full throttle shift points! Leave it alone. You can make the tranny shift at a higher rpm by replacing the secondary spool with part# C4OP-7C053-A or by replacing the entire governor with part# C4AZ-7C063-B for your 69 tranny.
While you are playing with the tranny you should consider a TransGo reprogramming kit# 47-2. That kit will give you the ability to manually hold it in any gear for as long as you want and to downshift to any gear regardless of your speed. It will still shift automatically when in drive. Combined with the new governor it will auto-shift in drive at 5800 rpm with your foot on the floor. That will get the most out of your cam and keep your times as consistant as the rain in Seattle.
Paul
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post #6 of 13 (permalink) Old 04-25-2007, 04:19 PM
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Shift points C4 change ?

I had a thought as I was posting the last post -
Is your kick-down linkage on, working and adjusted correctly?
With the throttle held wide open (engine OFF) and the kick-down linkage held all the way depressed there should be .060" between the adjustment screw and the pad on the throttle linkage.
Make sure that you are getting wide open throttle when the pedal is on the floor - have somebody press the pedal and then see if you can open the throttle any more by hand (again with the engine OFF).
Paul
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post #7 of 13 (permalink) Old 04-25-2007, 09:37 PM
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Shift points C4 change ?

Paul...is this governor and secondary spool valve still available????
I know reducing the secondary valve(GOV) weight will raise the full/part throttle shift points....

I have a transGo 47-2 in my 67 GT350, and it works great, but for years I could not have the tranny auto downshift to first while in drive, at any speed over about 20mph,,,very aggravating, when the chevy boys can buy governor kits anywhere...

I know the modulator will alter your shift points, and firmness....My Shelby now is almost perfect, for my application..

I wish the Ford info was easier to find....for us vacuum modulated guys...

Thanks for all you do....I am no expert by any means!!!
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post #8 of 13 (permalink) Old 04-26-2007, 07:36 PM
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Shift points C4 change ?

Your C4 is not supposed to downshift into low until you are almost at a stop. Why would you want it to downshift at 20 into low automatically? All that does is tear parts up.
The Modulater can fine tune part throttle shifts up from 1-2 and from 2-3 but it should never be adjusted to the point where it causes the tranny to downshift at 20 mph. You might as well just disconnect the vacuum hose to the modulator. That will do the same thing. The limit of adjustment on the modulator without hurting the tranny is 4 turns in either direction from the center point.
If you adjusted the transmission to make it shift into low at 20 mph you have ruined the modulator.
The governors were still available the last time I bought one. I don't see many pre 70 C4's though. The Governor (and modulator) are only supposed to control up shifts, not automatic downshifts. If you want to downshift before the tranny does then pull on the shifter.
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post #9 of 13 (permalink) Old 04-26-2007, 07:38 PM
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Shift points C4 change ?

PS to my last post. You use either the governor or the valve - not both. It would be a waste of time to replace the spool in the new governor with the same one.
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post #10 of 13 (permalink) Old 04-27-2007, 10:44 AM
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Shift points C4 change ?

I have a Shelby GT350...289 with a Paxton, with a higher auto downshift speed, it greatly helps, the combo accelerate....droppin to second at 25mph, is a slug.....this aint no stationwagon!!
Removing weight from the secondary valve, really woke the car up....
Been trying to fix this problem for years....chevy guys have commercial kits to reprogram their governors, but the Ford C4 is like a secret...hard to find parts, or the correct info.....
Presently very happy with my setup...

I am limited by having to use my date coded 67 C4....had the imput shaft upgraded to the 26 spline,,,,

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post #11 of 13 (permalink) Old 04-28-2007, 10:38 PM
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Shift points C4 change ?

If you are using the larger input shaft why don't you get a 70 or later tranny? Are you using the special modulator for supercharged engines?
If you already lightened the secondary spool then you don't need the governor. When you say "dropping to second at 25mph" are you talking about kick-down under hard acceleration from third? ( a shift from 3-2 under power should happen at speeds a lot faster than 25. At 25 it should almost go into first under hard acceleration.
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post #12 of 13 (permalink) Old 04-29-2007, 03:54 PM
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Shift points C4 change ?

I try and keep the car as stock as possible, car is very original.....so I keep the '67 C4 in the car,,still using a stock white stripe modulator..
In stock configeration, the car would kick down to second, with speeds over 25 mph..never to first......
With the lighter secondary valve, and lighter spring....the car downshifts to first, under about 35 mph, only if accel is fully depressed...and is really fun to drive....Normal driving, car functions as normal, will downshift to second, as would be expected....

I have owned this car for 25 years, and have tried many times, different shift kits, etc...Governor alteration really cured the problem...



<font size=-1>[ This Message was edited by: markboss on 4/30/07 6:56am ]</font>
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post #13 of 13 (permalink) Old 05-06-2007, 05:37 PM
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Shift points C4 change ?

Mark, i'm glad you finally got you trans where you want it.

I will sell this spring for $15.00 each which includes shipping if anyone is interested??
What I did was at least get the shifts close to 6000 rpm's.
Note, no mods were made to the large primary piston.

Hope this helps guys, also thanks for all of your previous input. V/R Bill Ambler

If you want this special lighter spring, e-mail me at
[email protected]
67 mustang coupe 6-cylinder
2003 ford lightning

<font size=-1>[ This Message was edited by: wsa111 on 5/8/07 6:41am ]</font>
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