transmission slipping, please give advise!

the shop i use gave me a $475 price to pull and build my c4. that was last week. mine would not pull off when cold. it took a couple of min. to warm up. i was told of the brake fluid trick. i put about 3 oz. in a warm tranny and the next time i got in it pulled right off. it has been working fine from then on. don't know for how long but for now it is great. jmo...frank...

 

Does it slip when you shift it manually? If you're not having a problem getting into reverse, then it's not the high clutch pack. You problably have have a clogged filter. Change the filter cuz they can get clogged. If that doesn't do it, it's probably in the valve body which means debris is clogging the passage for the high clutch pressure. A Transco shift kit will have you drill out that passage to make it shift faster & harder. It's called a Transco street & strip kit. That's what I put in mine. Comes with complete instructions that even I could follow. And I'm no tramission guy. You don't need to pull the transmission to do it. Cuz it's all in the valve body. Hope this helps. (Do not put brake fluid in it!)

 

Shift problems

Boy is this a familiar problem, my 74 comet has only 72k on it and I have to get it up to 25 to 30 mph to get to 2nd, then have to run it up to 60 to 65 to get 3rd gear, I have a vacuum modulator to put in it and hope to put it in this weekend, any tricks to putting this thing in? never have done any tranny work,
I only know it is mounted externally, but how does it remove? is it bolted in?
does anything have to be unbolted to get to it, if anyone can give me a step by step it would be appreciated. :confused:

 

Is your modulator threaded?
From what I know there is 2 types. Push-in(which is what I had before I plugged it off)
or screw-in. And thats all you have to do to get the old one off.

 

The screw in type is just that, use some channelocks or such to loosen it. There is a small metal rod that goes inside it and the valve inside the trans. Make sure it doesn't come out with the modulator. The push in ones have a o-ring on the end of it and a clamp that is bolted to the trans to hold it in. Some of the new modulator's have an adjustable screw in the center to increase or lower the shift points. They are set at the factory but you can experiment with the adjustment that suits your driving and trans functions.

 

Vacuum modulator

Well I near as I can tell there are 2 vacuum lines running to it, it is really hard to tell what's what, the one I bought has 2 places for hook up of vacuum lines, and it must be the plug in one, as it is not threaded, it has a small flat gasket ,
the part that appears to go itno the tranny is grooved around the end of it,
looking at it from the side -------)_ (--- ------> (into tranny)
_ _ _ _)--(_ _

Kinda like that. but there is no
other peice to it, there are holes in both ends.
Now, I am describing the replacement one, I will have to take the old one off to know for sure if this is the right one,

 

C4 Modulator

While everyone is going at this C4 modulator issue can someone tell me how long the "modulator pin" is? I t seems that the guy I got my Maverick from decided to take the freakin' pin out and then give me some other pin that sure would not go into my trans and let me install the modulator. So.....I did what I had to do to get it to work, I cut it with my dremel and rounded off the end and put it in. Seems to shift okay but I really need to know how long the "stock" pin is.

 

not running dexron fluid are ya?

 

i'm taking my spare tranny in next week for a rebuild. $350 is what i was quoted. this guy does them for a number of guys at the track.

 

High gear clutches toast, To much end play, Band toast and or out of adjustment, Sealing ring on servo blown, and or all the above. Have you tried a band adjustment?

 

Just did a homemade shift kit with my valvebody, got the same 2-3 flareup. Never had it before. Tightened the intermediate band to 1 turn off of snug, and lost most of it, but still have a little flare left, and am afraid to tighten it more. I think it is time for a rebuild (stock C4, 58k miles).

 

The 2-3 flare up on C4s usually becomes very noticeable after a shift kit has been installed.Most of the time a C ratio servo is recommened to stop this.

 

Mines got that 2-3 flare also. My trans only has about 3,500 miles on it, has a mild shift kit.

 

i dont want to read through all the responses... but i had similar probs with not wanting to shift

check your adjusting nuts.. if they have backed out, it will do that exactly.. mine did it three times and the shop that rebuilt the tranny kept tightening them.. and they would loosen... until the last time i told them either they fix it or i get my money back... and since it was still under warranty, they gave me another 1 year guarantee agasint the tranny... for the adjusting nuts


check those and make sure they are tight.. BEFORE opening up the tranny

and some modulators are threaded and push on... they have dif types...

i went through that when i got my tranny put in the first time

 

First off the band adjustment is 10. inch pounds not foot pounds. I have built quite a few c-4 trannys and the flare 2-3 shift is very common the fix is clearence ,when u rebuild them always use new thrust washers and the direct and forward clutches must be within .005-.010 of the minimum.

Its possible the modulater is causing the problem but what about the governor? Its bolted to the tailshaft inside the rear housing and willl cause the problem youre describing. But theres no way to tell without looking at it.