Another C4 went

[Elizabeth73]

c4 Auto Transmission

So about one week after I put the engine back in after new paint and a larger carb/intake, the transmission went.. First I couldn't put the car in park and it was shifting late..

I got home and put blocks under the car so it wouldn't roll. Now my "P" is neutral, and everything after Parks on the shifter are all drive.

Nothing wrong with shifter handle. Took the tranny out. Heard something rolling around in it when we put it on the table. Took the oil pan off quickly and saw this thing:

What is the technical term and where does it go? I do not know much about transmissions at all and this will be the first time I take one apart and rebuild/fix one.

 

[turtle5353]

c4 Auto Transmission

So about one week after I put the engine back in after new paint and a larger carb/intake, the transmission went.. First I couldn't put the car in park and it was shifting late..

I got home and put blocks under the car so it wouldn't roll. Now my "P" is neutral, and everything after Parks on the shifter are all drive.

Nothing wrong with shifter handle. Took the tranny out. Heard something rolling around in it when we put it on the table. Took the oil pan off quickly and saw this thing:

What is the technical term and where does it go? I do not know much about transmissions at all and this will be the first time I take one apart and rebuild/fix one.

If I remember right that is in there from the factory and just plugs the dipstick hole during assembly. When the dipstick gets put in then it usually falls down inside the pan and stays there. But I may be wrong! My mind aint what she used to be!

This also means your pan has probably never been off!

 

[jeremycfr]

It should be a simple adjustment to get the shifter handle lined up. Disconnect the handle where it connects to the trans, adjust the trans by hand into park and then reconnect. We had the luxury of a rack to do it.

As say all this while I'm sitting in a trans shop having mine looked at.

Sent from my iPhone using Tapatalk

 

[72HCODE]

yup that is a factory plug, that means nobody has been inside that trans since it was originally built.

they get pushed into the pan when the dipstick is inserted. they are too large to get sucked up by the filter so they usually just roll around in the pan for 40 years.

 

[imusa76]

it sounds like the shift linkage was out of adjustment.

 

[Elizabeth73]

Good guesses everyone, but to my suspicion, one of the bands was snapped completely off (I believe it is the intermediate band, near the front end of transmission, see pics). I am thankful that it is a simple problem that I can fix on my own.

Thank you for telling me what that piece was. Do I need that when I put it back together? Which way does it face in the dipstick? I guess it is a good sign that no one has dropped that pan. Wow, a 42 year old transmission. They don't make them like they used to.

Here are some picturesoh and yes, I am girly at times and paint my nails once in a while, after all I am a girl lmao ;P )

 

[Elizabeth73]

Would THIS kit work? It has different options, which one do I chose? (1973- up 4x4, 1973-up 2x4, or flex band style?)


How the heck do I get this off? I don't see any bolts and it is stuck on there good. Am I missing something?

 

[mjlan]

Elizabeth-

Is there a tag on the outside of your trans, perhaps underneath a bolt head somewhere? This would be the best way to ID what you have, there were a couple different types of C4's, the main difference being dipstick location- pan-fill vs. case fill....

The picture shows the font pump, and I am not 100%, but I think it has an external OD O-ring that seals it to the case bore. You may need a puller to get it out...

Do you have a shop manual? I think there's some good info there on disassembly/ rebuild. Maybe downloadable from the Wiki?

 

[Elizabeth73]

UPDATE #2




So the transmission was rebuilt and I tried taking it for its first drive today. I can now move the shifter into all gears so thats good. But when I took it for a drive the car would not go into 3rd gear.

Checked the vacuum modulator and all lines are connected and there is vacuum.I think the next step is seeing if I have a stuck 2-3 valve in the valve body..

This is a huge disappointment. I am almost tempted to bring it to a transmission shop. I am so frustrated with this transmission that I had moments where I wanted to put a for sale sign on my car lol.

I would never sell it, but I was so frustrated today that the thought crossed my mind (which has never happened before). I guess this is what happens when you get your hopes up.

Could be worse though and hopefully it will be a simple fix. Trying again another day..

 

[jeff8877]

One thing you might try first before opening back up is the linkage. Disconnect the shifter linkage, put the back wheels in the air and see if you can manually shift the trans through the gears. If your linkage wasn't adjusted right it could prevent getting to third gear.

 

[Elizabeth73]

How will I know it is in "D" and not 2nd or first?

I only ask because if I manually put the car in 1st and move the lever to 2nd and then up to D, the car goes back to first gear while on "D." So it goes 1 2 1 N R P IF I shift manually from first gear. It is kind of hard to explain online.. Easier said than typed but I hope you can see what I am trying to say.

However, If I never manually shift to first gear then "D" acts as second. Something seems wrong internally.

 

[Elizabeth73]

One thing you might try first before opening back up is the linkage. Disconnect the shifter linkage, put the back wheels in the air and see if you can manually shift the trans through the gears. If your linkage wasn't adjusted right it could prevent getting to third gear.

I am kind of confused on the linkage to be honest. there is one coming from the steering column, there is the kick down cable, and the shifting arm from the inside of the car. I have no idea which one needs adjusting or how to even go about that.

Modulator was pulled again along with the pin and valve to make sure the valve was facing the right direction. That was fine.

Next thing to check would be the 2-3 shift valve in the valve body.

I think I will take it on the street late tonight when there is no traffic. Maybe a valve is stuck and just needs some coaxing to move. I haven't really pressed the gas because I haven't taken it on the road, only in my neighborhood.

 

[jeff8877]

My thought was to unhook the shift rod at the manual trans lever (see pic). Also, turn the key on so that the column lock rod will release letting you shift through the gears. Put the back wheels in the air and start the car. You can then manually shift through the gears where the shift rod attached to trans. This will eliminate all possible linkage issues and let you know if it its trans or linkage related. The procedure on how to adjust all the linkages is in the shop manual.

 

[Elizabeth73]

Okay I see what you mean.

I don't think it is a linkage problem because when the lever is in Park, so is the transmission. With the lever on Reverse the car does go into reverse. So that is all lined up. I can manually shift the car from first to second but in "D" the car returns to first gear..

Should I try tightening the Intermediate band a turn? I originally tightened it to 10ft/lbs and backed it off three full turns, but it seemed super loose. I hope my servo is working.. that is another thing I think I need to consider since it is the factory "A" servo.

 

[jeff8877]

The shop manual says torque to 10 ft lbs then back off EXACTLY 1 3/4 turns.

 

[Don C]

I agree with Jeff, check the linkage adjustment before you do anything else. The procedure from the shop manual is:

1. Position the transmission selector lever in D position.

2. Raise the vehicle and loosen the manual lever shift rod retaining nut. Move the transmission manual lever to the D position, the third detent position from the back of the transmission.

3. With the transmission selector lever and the manual lever in the D positions, torque the attaching nut 10 to 20 ft-lbs.

4. Check the operation of the transmission in each selector lever position.

 

[Elizabeth73]

I will be pulling valve body to check that the valves are not stuck. While I am at it I will do some air tests to make sure my servos are working as well as the governor. I found this short but informative video online to show the process on the c4 transmission. I have never done this before, seems simple.

[video=youtube]

 

[Mesozoic]

Not sure if you're trying to keep your car as original as possible, but a good option in lieu of the C4 would be a 4R70W. I'm loving mine!

 

[Elizabeth73]

Not sure if you're trying to keep your car as original as possible, but a good option in lieu of the C4 would be a 4R70W. I'm loving mine!

What company did you get it from and how much did it run you if you don't mind me asking?

I am pretty sure this is a fixable problem, I just want to be able to fix it before I think about bringing it to a transmission shop to fix it. I don't want to spend over five hundred for a shop to fix it when I could put that toward a new tranny. (Have looked at the C4 Performance Automatic transmissions like the "Super Street Transmission" which runs about $1700)

As a college student, I really REALLY have no money like that.. the car would sit for years before I could even think about buying a transmission. Or maybe I would take out a loan or something from the bank.

Wish me luck tomorrow! Pulling valve body and I hope to find a stuck 2-3 shift valve. At least that is an easy fix!