C-4 service

So I bought a 1970 Ford that been laid up for nearly 40 yrs. Owner stated the trans was leaking when parked but shifted fine. So I finally got around to getting the car running, the trans wouldn't go into gear. I put almost 4 qts before she moved. I am going to drop pan and service trans, should I drop valve body? What gets restored,  or serviced? I drove car into garage and do not see a leak.

Not a lot to service at a basic level. Fluid color should tell you a little about overall condition. If still fairly red then probably in good shape and a sign the transmission has been serviced. If dark and burnt smell then could have some issues. I would start with a complete fluid change which would include draining the torque converter. 

Check and see what' s in the pan when you drop it.  Look closely for any signs of metal flakes or cellulose material from the bands or clutch disc.  Check the old filter over good also when changing it for any foreign material. I wouldn't drop the valve body unless I had a reason to. Make sure you stay with type F fluid.  Should take about 10 quarts to fill back up.  I would also replace the vacuum modulator valve while your under there. I would replace with an adjustable one.

Test drive and see how it runs.  Pay attention to the shifting speeds and how smooth they are.  Take note in performance between being cold and after it warms up.  If it is shifting smooth and no noticeable slippage or hard shifts the you should be good to go. 

If you experience any slippage or hard shifting then the bands may need adjusting or rebuild may be necessary.  Also would run a pressure check at that time too.

I do not remember a drain plug on a c4 torque converter, I seen them on the aod??

In addition to what Kilgon said, I would look for any obvious signs of leakage before you pull the pan. The shift shaft seal is a common leak location. If you let it sit a few days before you start working on it the torque converter may drain down enough to fill the pan until it starts leaking.

I do not remember a drain plug on a c4 torque converter, I seen them on the aod??

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No drain plug on torque converter.

I didn't think so

I didn't think so

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Partially true.  Some C4's did.  The earlier models did and then it was a hit or miss over several years.   Below is a original factory C4 torque converter. I would take the few extra  minutes and check. 



Drain plug in torque converter Ford C4 transmission

Agree on the drain plug, my first Mustang, a '73 F-code w/C-4 had one.

To be honest, you should expect to need to do a trans rebuild sometime in the near future. 50 year old seals are only going to last so long.

Agree on the drain plug, my first Mustang, a '73 F-code w/C-4 had one.

To be honest, you should expect to need to do a trans rebuild sometime in the near future. 50 year old seals are only going to last so long.

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Your probably right, but it move forward and reverse so If i can get it on the road in next few week. Is the drain acc. with trans in? Looks like its between the flywheel and converter.

Alex

P.S

No trans oil on floor this morning, will check modular line for fluid soon

If I remember correctly, if it is installed correctly with the correct flex plate and has the drain plug you can access by removing the inspection plate and rotating and there should be a hole in the flex plate lined up with the drain plug to access it.

If I remember correctly, if it is installed correctly with the correct flex plate and has the drain plug you can access by removing the inspection plate and rotating and there should be a hole in the flex plate lined up with the drain plug to access it.

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Thank you, will look into it when Im ready to service the trans. Is  the correct modulator with white stripe?

If I remember correctly, if it is installed correctly with the correct flex plate and has the drain plug you can access by removing the inspection plate and rotating and there should be a hole in the flex plate lined up with the drain plug to access it.

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100% correct. Pull the small inspection plate and pull the engine over with a breaker bar or use a remote starter.

Is  the correct modulator with white stripe?

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What's the application?

1970 c4

1970 c4

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1970 C-4 in a ? behind a ?

1970 c4

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White stripe and I do believe be screw in.  Later models had push in held by bracket.  Extra FYI - If you want to adjust the shifting speed there is a screw where the hose goes on in the nipple.  Use a small flat tip screw driver.  Turn clockwise to firm up and delay the up-shift of the transmission. Turn the adjustment screw in a counterclockwise direction to speed up and soften the up-shift.  Do one turn at a time and test drive.  Do not adjust the screw more than four turns in either direction.  

1970 c4

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1970 C-4 in a ? behind a ?

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Torino, 302

1970 c4

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White stripe and I do believe be screw in.  Later models had push in held by bracket.  Extra FYI - If you want to adjust the shifting speed there is a screw where the hose goes on in the nipple.  Use a small flat tip screw driver.  Turn clockwise to firm up and delay the up-shift of the transmission. Turn the adjustment screw in a counterclockwise direction to speed up and soften the up-shift.  Do one turn at a time and test drive.  Do not adjust the screw more than four turns in either direction.  ,

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Sounds good, after install will play with the screw, thank you

As long as the transmission is original to the car, it takes the Motorcraft TM-2 / C4AZ-7A377-B modulator, which is the white stripe screw-in model. If it's been swapped to a later transmission, there will be a bracket and screw holding the modulator in place.

https://www.rockauto.com/en/moreinfo.php?pk=45258&cc=1141074&jsn=3393

Don't misplace the internal rod when you swap it out.

Was going to make few larger orders from Rockauto, they charge shipping, tax and I have to pay for returns, even cores.