Author Topic: 67 C4 transmission shift kit removal  (Read 2582 times)

Offline socalgt

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67 C4 transmission shift kit removal
« on: January 11, 2016, 11:33:49 PM »
I had my transmission fluid and filter changed and the shop confirmed a shift kit had been installed.  I don't care for the harder(though quicker)shift.  How difficult is it to reinstall the stock valve assembly to restore the original shift.  I see them available on Ebay.  I don't want to attempt it and find out there are small parts that will fall out during the removal and replacement of an original valve assembly.  Perhaps this is something better left to a shop with the car conveniently on a lift rather than me doing this with minimal clearance that jack stands would provide?  (I was hoping that if replacing the entire valve assembly there wouldn't be any small, loose parts to be worried about)

Offline 67gtasanjose

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Re: 67 C4 transmission shift kit removal
« Reply #1 on: January 12, 2016, 05:56:29 AM »
The valve body, as a unit, easily lifts out on a C4. Remove only the visible 7/16" socket size bolts and it comes right off without any loose parts falling out.  (similar for the C6 trans for anyone reading)

One think to take note of prior to assembly and to check after assembly but while the pan is still off. Notice while the valve body is down how the manual valve to the shifter linkage engages the valve body (also the passing gear linkages) Line those up as you lift the valve body into place and test both for proper operation prior to installing more than (say two) all the valve body bolts. Also test PARK for locking the driveshaft. The passing gear should operate a full range forward and back with a notable spring pressure.

Hope this helps, I was changing these by age 14 so I am sure you do not have to be an expert. The things I pointed out were the mistakes I made and on one occasion at least, I had to pull the pan back down because "I missed" aligning things up.
Richard Urch

1967 (11/2/66, S.J.) GTA Luxury Coupe, 289-4V w/Thermactor Emissions, C-4, Int./Ext. Decor +many options

2005 (04/05) GT Premium Convertible, Windveil Blue, Parchment Top w/Med. Parchment interior,  Roush Body Appointments

Offline socalgt

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Re: 67 C4 transmission shift kit removal
« Reply #2 on: January 12, 2016, 10:21:20 AM »
Thanks for the info....good to know, all of it.

Offline J_Speegle

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Re: 67 C4 transmission shift kit removal
« Reply #3 on: January 12, 2016, 03:39:32 PM »
Depends on what kit was used - often its just a swapping of the plate between the two halves of the valve body. If I was looking into this I would find out if the valve body still had its ID tag attached and what number it was (to help determine if it was the original) then find a picture of a Transkit to see what all it originally included so that it can provide you a guide as to the possibilities

Not sure how many transmission shops your going to find with workers who were alive when these kits were popular but this is not a big job and your not really disassembling the whole thing. Just a hand full or so of little springs and round beads

While your at it make sure that your getting full vacuum to the modulator valve (an old trick to stiffen the hits) and what valve is installed.

Its a start ;)
Jeff Speegle

Anything worth doing is worth doing concours ;)

1967 eight barrel

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Re: 67 C4 transmission shift kit removal
« Reply #4 on: February 09, 2016, 01:48:02 AM »
It depends on what kit it is in it. I don't think he mentioned it being a "manual valve body". The B&M that was installed in my '68 coupe required a check ball and one port to be drilled out. Obviously. the drilled port can't be changed at this juncture.

Offline 70cj428

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Re: 67 C4 transmission shift kit removal
« Reply #5 on: February 09, 2016, 07:29:55 PM »
Quote
It depends on what kit it is in it.

And here lies the problem....

People have been modifying valve bodies since there were valve bodies, and most shift kit manufacturers  have there own way of doing it. Some are as simple as swapping the intermediate plate and adding a few shims, some involve enlarging holes and replacing springs, and some involve replacing hard parts. If you don't know EXACTLY what was done, undoing it may be really difficult or impossible. If you get the trans timing or pressures screwed up by partially undoing some mod's, You may kill the trans in short order.

Unless you did the install or have the kit's instructions, I'd STRONGLY recommend just replacing the modified valve body with another unmodified one. Replace the modulator with a stock one and you have a very, very good chance of being happy with the results. ( I've only ever seen one kit way back that replaced the governor spring, located in the tailhousing).

As always, JMHO, John

1967 eight barrel

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Re: 67 C4 transmission shift kit removal
« Reply #6 on: February 10, 2016, 04:10:38 AM »
+1 on John's commentary.