C4 leak at shift shaft seal

Arter · Sep 13, 2009

Just looking for some help. I have been told that c4s can warp or become elongated where the shift shaft exits the trans body. Is this true or common and if so I am looking for any suggestions on how to get a good seal. I have replaced the seal 3 times, and it continues to leak. If I have to I will just buy a used c4 and swap the guts. I guess I am looking for a cheap fix.

4lofun · Sep 13, 2009

is the shaft scored with grooves? are you installing o ring before the kickdown lever? i never heard of a warped case in that area.

Arter · Sep 14, 2009

Thanks for the reply. There isn't any scoring on he shaft, but it might be the o ring on the kickdown lever. I guess I will just have to remove it all again and check the o ring. The lever did break free from the shaft and has been welded back in place. Do you think it might be a bad shaft? If so do you know where I would be able to buy a new shaft ans shift lever? Thanks agin.

blubuckaroo · Sep 15, 2009

Arter,
There are two shafts, one inside the other. The outer shaft is the shifter shaft. You have to remove the valve body from the transmission to get to the seal on that one. The inside shaft is the kick-down shaft. There is an o-ring (sometimes two stacked up) just under the kick-down lever that seal oil from comming out from between the two shafts. You only need to remove the lever from the kick-down shaft to replace that one. A lot of times you can tell which one is leaking by where the drip is coming from. If it's dripping from the shaft it might just be the o-ring. If it is running down the case, it is more likely the inner seal.
BTW, if you have thelever welded to the shaft, it's FUBAR. Find another shaft.

Arter · Sep 18, 2009

Thank you for the reply. I have not had the chance to tear it apart yet but I removed the kickdown linkage and I think the o ring is missing all together and that would explain the puddle of tranny fluid on my garage floor. Would you recommend double stacking the o ring or is usually sufficent? Any idea who would carry the right size o ring. It was a bit of pain getting the main shaft seal the last time I changed it. I am going to try checkers/Autozone and NAPA,but any other ideas would be great. Thanks again.

haydenjsle · Sep 19, 2009

I had both my seals replaced--still couldn't get it to stop leaking. Finally ended up replacing the whole case--problem solved. My tranny tech. said the case was worn--don't remember if he said it was very common or not. Seems like there was excessive play between the shaft and the old case also--new one seems slightly tighter. Hopefully, it's just the kickdown o-ring in your case.

Viperwolf1 · Sep 19, 2009

Arter said:
Thank you for the reply. I have not had the chance to tear it apart yet but I removed the kickdown linkage and I think the o ring is missing all together and that would explain the puddle of tranny fluid on my garage floor. Would you recommend double stacking the o ring or is usually sufficent? Any idea who would carry the right size o ring. It was a bit of pain getting the main shaft seal the last time I changed it. I am going to try checkers/Autozone and NAPA,but any other ideas would be great. Thanks again.

The correct o-ring is not really an o-ring at all. It's a special H-type ring. You can get them at Transtar Industries. I have used two slightly different sized o-rings together to get a good seal before also. Get a variety pack of rings and find one that seals the outside diameter well and another that seals the inside diameter well. They need to be very thin cause the depth of the well in the shift shaft is short. Just make sure they don't cause the kickdown lever to bind.

ep67bro · Sep 21, 2009

I have a c4 in my wifes that I cant get to stop leaking too. I have had the inner seal replaced and have replaced the o rings and it still pukes trans fluid all over the floor. And it is definatly coming from the shifter linkage. I hope it is not the case.

BwoncoHowie · Sep 21, 2009

You might have better luck getting the o-ring from a transmission shop. The quad seal that viperwolf mentioned was developed in the 90s by a kit manufacturer long after the c-4 went out of production, these seals havent always worked well for me but you could give it a try. However the older original style o-ring is same as what is used on the vacuum modulator. Trans shops usually have extras left over from kits and will probably give you a couple for free.

All lever seals arent created equal either. There is an overseas manufacturer out there that has flooded the parts market with junk seals so be wary of that and get your seal from a trusted source that is an expert when it comes to transmissions.

Arter · Sep 25, 2009

You guys rock. Thanks for all of the replys. I have some time off next week and I am gonig to go on a scavenger hunt to see what type of o rings I can round up. When I get it all back together I well let everyone know how it goes. Thanks again you have all been a lot of help.

doosey · Jul 24, 2011

how do you test a neutral safety switch on a 73 bronco, it was bypassed before snd i adjusted the shift linkage reconnected the harness from the trans, switch seems to be lined up by the no 43 pin in the side of the switch, using a no 43 drill bit it goes in the hole about 1/2 inch truck wont start?

C4 leak at shift shaft seal

Arter

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4lofun

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blubuckaroo

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Arter

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haydenjsle

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Viperwolf1

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