turning a C6 into a married C6

[usmcjones1988]

ok i fixed the shifter i think it was off by a little but now i have P R N D 2 1, driving it around it feels like it starts off in second and completely misses 1st and starts off in 2nd, or it just a really smooth shift which i dont think so but it is still take a little of it to change for 2nd to 3rd.

[usmcjones1988]

well from what i read it looks like the diaphragm broke and im sure that could be some of the reason why its not working right. I am looking at all the different kind of valves and have to idea which one i need here is where im looking at them at: http://www.oreillyauto.com/site/c/searc ... +Modulator.

[Donnie]

What year is your trans? Do you have a screw in or a push in modulator ? I don't recall that we discussed the year. Engine size again? stock or cammed up?

[usmcjones1988]

As far as i know its a 1978 trans connected to a 460 and stock, but not completely sure. im think its a push in because there is a piece of plate that looks like it holds in in and than there is a screw that hold the plate in.

[Donnie]

I think C6 went to push in in 73, not sure ...........earlier screw in was white or green..
I can check tomorrow, if that is not too late....The C5AZ is for a full size car, the Oz , a smaller vehicle . I haven't done any in a while, but I have used most everything, What is in it now?
There are 2 things to consider when choosing a modulator...
There are 2 diff. dia.'s of the diaphragm. & many diff. spring tensions.
post up tonite if you have not bought anything & I will check my notes tomorrow.......Donnie

[usmcjones1988]

ya i haven't bought anything yet im waiting till this weekend to yank the old one out and try and find a new one.

[Donnie]

If the '78 C6 / 460 came from a truck, not likely,---it would like a D3TZ=====brown stripe
75 to 96 car 460/ C6-----------D5AZ=================purple stripe
77 to 96 most common one that I used was =========green stripe
Diesel with C6 and the POS vacuum contraption---------Black stripe
There was a mechanical modulator (aftermkt.) made for diesels as they have no vacuum, they were costly & cable operated and HARD to find.......
In your case I would go with a green stripe & set the weight @ 11 # to start
If after all this you find that you are getting 2nd gear starts, let me know & I will help you qualify the gov or a hung tight shift valve.............Donnie

[usmcjones1988]

thanks ill pick it up tomorrow if i take off the old one will i see a strip on it?

[Donnie]

You should, not all are easy to see, wipe it clean & be sure to check the hose inside for oel. use a qtip, should be tight & dry...watch the pin that will fall out..place it in the new modulator with a dab of vaselene to keep it in place when reinstalling....good luck.......Donnie

[usmcjones1988]

yep im am on my way to the parts store to get the valve now ill let you know later to today how it goes

[usmcjones1988]

ok i got a green stripe one how do i know when it is set to 11 all it has is a little screw with no marking to know what it is set to?

[Donnie]

Mostly they come preset, unless someone else has been adjusting it....I posted earlier on setting the spring tension, but if this is new , rite out of the box, I wouldn't worry.....stick it in.
Some times people get carried away with the screw & start twisting it until they get lost, then they need the scale to get back to base...........Go for it..........Donnie

[usmcjones1988]

ok well i put it in and it seems to be shifting alot better and i changes the vacuum lines, but it is still holding back in 3rd when i let off the gas so im still thinking i need to change the governor.

[Donnie]

Shift it manually, run it up to 25 in manual low, shift it manually to 2nd, can you feel this shift???
run it up to 50 in 2nd then shift to the D position, can you feel this shift into 3rd?
If you can, then you have all 3 gears & thats all there is..It will hold back slightly in 3rd, that is normal, there are no more gears..SEE IF YOU ARE GETTING 3 GEARS following this method.......
If not, start out in the manual 2 position, get it up to 10-15 mph & pull it into manual low, What happens.........I'm gone for the day.........later , Donnie

[usmcjones1988]

i am for sure getting all 3 gears so it is normal for it to hold back a little bit in 3rd? If that is true thank you for all your help its shifting alot better. I know who to talk to for transmission for now one. Again thanks for the help.