Topic: C-4 transmission slipping in 68 coupe

[stephane]

Hello. I've had a transmission cooler that's gone bad. I replaced the rad, drained the transmission. I filled it up with dextron 3. Now the tranny slips on passing gear?? Did it ruin my tranny, or is it the oil that is not the right grade? The tranny was working fine before. Any info would be appreciated
Steve

[Soaring]

Wrong fluid.  C-4s take type F. 

[stephane]

Hi.  I drained the tranny, and the torque, and put type F fluid, still slipping on passing gear. the other gears seems OK. Is it time for a rebuilt, or is there something else I can try?

[Soaring]

Tighten the bands.  If you don't know how, get back. 

[stephane]

Hi soaring
I read your latest post about just about anything. Thanks for posting, real interesting stuff. I'll try the bands TKS
Stephane

[stephane]

I've tried to set my intermediate band, I removed the jam nut, and I can screw the stud all the way in the tranny, or all the way out. What does this mean?

[Soaring]

It means you don't have a chart to tell you how much ft. lbs to put on each of the adjusting screws.     Make sure you have a good and small torque wrench and don't tighten the bands any tighter, or looser than this.
Intermediate band is the front one with adjusting nut on the drivers side.

Low reverse band is the rear most one with the adjusting nut on the passenger side.

Adjustment procedure:

INTERMEDIATE BAND
1: remove and discard locknut and install a new one (more than just a good idea.)
2: torque adjusting screw to 10ftlbs. (thats the one inside the nut, not the nut itself)
3: Back off adjusting screw exactly
a. 1 1/2 turns on 1964 C4
b. 1 3/4 turns on 1965-1981 C4
c
4: Hold adjusting screw from turning and tighten locknut


LOW REVERSE BAND
1: loosen lock nut several turns
2: torque adjusting screw to 10ftlbs
3: Back off adjusting screw 3 full turns
4: hold adjusting screw from turning and tighten lock nut


10 ftlbs isnt very much so you will need a very small ftlb torque wrench. If you can find one that has both inch lbs and ftlbs on it, that would be the one to use.
________________

[stephane]

I hate to sound like an @$%, but I don't feel any tension on the stud when i scew it in??? Is it that tempermental? I saw a few places that said inch pound, but most reliable site was foot pound. I do have a good torque wrench, and it is set at 10, you can click it with a small wrench on it. Is it possible that my band is broke? I did not find anything in the pan.

[Soaring]

If you tightened the bands as per specs, and the passing gear still slips, it could be one of two things.
The band needs to be replaced, meaning an overhaul of the C4, or your kick down rod has been bent and needs to be looked at for damage.  Meaning, it is not completely engaging. 

[stephane]

The rear settings was about 2 turns, but I can't get anything on the front band adjusting strut. Is it a big job to fix that, can it be done on the car? Should I just call it quits, and rebuilt her. It was shifting fine until I ran antifreeze thru it (bad trans. cooler). What kind of kits would be great on these tranny.

[Soaring]

What is the condition of your kick-down rod?  If it is in good condition, and you want a passing gear, then your band needs to be replaced if you can't adjust it.  If it was mine, I'd have the tranny overhauled, because if the band is bad, or broken, then it won't be too far down the road where the others will need replacing.  Sounds like you may have a worn out C-4.