C4 won't shift into 3rd gear when cold

It sounds as though you are experiencing a 2/3 lockup. You can probably get rid of it with an "R" servo or maybe by adjusting your intermediate band. Get the specs from the folks you bought the parts from. Most of the time modified valve bodies don't use factory adjustment specs.

Originally Posted by PaulS1950

It sounds as though you are experiencing a 2/3 lockup. You can probably get rid of it with an "R" servo or maybe by adjusting your intermediate band. Get the specs from the folks you bought the parts from. Most of the time modified valve bodies don't use factory adjustment specs.

Okay, I'll work on adjusting bands and replacing servo.

What about the kickdown never saying hello to second gear? It won't downshift unless you gas it enough to drop into first gear.

PS - I almost bought a manual valve body, dammit. I could've got a manual VB with trans brake for about the same price.

But I didn't want to spend the money!

Okay, it's official; Installing a new TCI valve body did NOT fix the problem of a free rev neutral instead of third when cold.

After adjusting the bands to spec, I had to drive a mile before it would go into 3rd gear (just like it was doing before). If I pull out in drive cold it won't shift out of first at all. If I manually shift from 1-2 it shifts. If I manually shift from 2-3 it just free revs (until it gets warmed up).

Once warm it shifts okay both manual and in drive.

Now what? I'm getting frustrated.

Since it is repeating it org failure now i would say bands are adjusted right.

I am thinking the servo is sticking.

Just tossing this out to see what the real guru's think..
Learned how to rebuild my C4 from the info and help of this board.

Originally Posted by forthman

Since it is repeating it org failure now i would say bands are adjusted right.

I am thinking the servo is sticking.

Just tossing this out to see what the real guru's think..
Learned how to rebuild my C4 from the info and help of this board.

I ordered a TCI servo from Jegs. We'll see what that does.

I appreciate all the help I got here! Paul has been great. I just got a little frustrated because I have R&R the valve body 3 times. Spent $250 on a new valve body and kickdown linkage. Now $120 on a new servo. Add that up and I could've had a manual VB with transbrake?

Hate when that happens!

The only difference between 1st and 2nd is the application of the intermediate servo. It stays in first until the servo applies - then it is in second.
Third gear must disconnect the intermediate servo and apply the High/reverse clutch. If it free revs when it should be in high then the servo is released but the high / reverse clutch is not applying. Since reverse works when the C4 is cold then the clutch pack is operational. the same symptoms with two different valve bodies points to linkage adjustment.

So if the band stuck applied, servo stuck.
I was thinking is why he stayed in 2nd gear. And why it seemed in 2nd and 3rd at same thime.
Guess linkgage out of whack would do the same thing.

A good valve body, servo and cooling. Will keep the old c4 shifting smart and lasting long.
So no money wasted i am thinking.

The Redneck transbrake manual valve body i have i love for the drags.
Might be a bit dangerous on the street. Hit that transbrake at the wrong time.

My new TCI servo should be here today; we'll see if that fixes the cold shifting problem. The linkage is adjusted properly.

On the subject of the kickdown malfunction; When I'm driving along at 1500 rpm in third gear (drive) and want to speed up and slowly press on the gas it will just keep lugging third gear until I press the gas down 3/4 of the way where the kickdown sends it into first gear which sends the rpm to 5000 and makes it do a holeshot. Why can't I get it to drop into second gear for a more reasonable acceleration? If I'm cruising along at the same speed in Drive and begin slowing down to say 15 mph it will drop into second gear by itself when the throttle is at idle position. But If I try to accelerate from say 1500 rpm in third gear it will not drop into second gear; I have to manually select second gear to avoid having the kickdown throw it into first gear.

Any ideas on the kickdown malfunction?

I am not sure. But the kickdown thing, is the vacum signal/mech. operation i thought.
"this is why i went manual"
The kickdown lever i think changes the valve body fluid routing. Sorta over rides the shift selector.
I am thinking the modulator,govenor,shift down lever all wor together.

Then might be when you get the Org. problem figured out the down shift thing might go away.

I was wondering if low fluid pressure could be part of the problem?
Ever checked to see what you are getting for pump pressure?