Ford Mustang Forum banner

21 - 40 of 41 Posts

·
Registered
Joined
·
7 Posts
C4 leak

My C4 is leaking from the shift shaft, has anyone out there replaced the seal, can it be done with the tranny still in the car, or does the seal need to be changed from inside the case? Attached is the area I am talking about.

Any advise appreciated.

Jeff
 

Attachments

·
Registered
Joined
·
1,806 Posts
Yes you can replace both the seal and the "o-ring" with the transmission in the car. the hardest part is getting the valve body back in place properly.
Before you replace the seal try repllacing the "O-ring " on the small shaft first - this is where the C4 most often leaks around the shaft area. To do this:
Remove the nut and linkage from the small shaft (kick-down shaft).
gently push the shaft toward the transmission until you can see the "O-ring".
Pull the shaft back toward the outside of the transmission to expel the "O-ring".
Put some Vaseline on the new "O-ring" and install over the small shaft.
Replace the linkage and tighten the nut.
You shouldn't even lose more than a couple of drops of fluid.
 

·
Registered
Joined
·
2 Posts
No lift

It is impracticle to attemp this mod without a lift. I hav a 65 that is leaking a little at the selector shaft and the shop wants $250.00 to replace the O ring stating they need to drop the TB . Your post is excellent. Newbie

Tks

Dallas
 

·
Registered
Joined
·
310 Posts
Hey Steve thanks a lot your article helped me out a lot previos person cut the gear selector bracket in half (don't know why he changed to a 5spd)so there was no place to connect the shifter rod to. So infoming me on how to replace this gear selector shaft became real easy. Txs again. :wavey I went back to the original C4 that I got with the car.
 

·
Registered
Joined
·
1,513 Posts
After reading this excellent posting, I had decided it probably described what was causing the leak around the gear selector shaft in my '66 Mustang C4. But I finally got around to looking at it yesterday, and it appeared that the O-ring was seated properly on the shaft; i.e., not on the flat. The nut was not loose. There was quite a bit of movement in the shaft after I removed the nut--I could slide it to where it almost disappeared into the transmission case. But it looked to me that once I tightened the nut down it would pull it all the way out so the O-ring would seal. The old O-ring wasn't nicked or anything, but was pretty hard, so I replaced it. It wasn't exactly the same dimensions as the old one, but it fit in the recess in the case and seemed to seal around the shaft. No leaks when I refilled the tranny, but I won't be able to start the engine for a few days because of other work I'm doing, so won't be sure until then.

I should add that this isn't the original transmission. A friend swapped it out about 20 years ago with a rebuilt one. So I guess it's possible the problem had already been fixed.
 

·
Registered
Joined
·
2 Posts
c4 wont engage

i am having an inssue with my c4 atuo trans not engaging in gear and i can't figure it out. could it be the inner input shaft not fully inside the stall converter or would it only be a selector problem? i only have a couple weeks before i deploy and i have to have the car done before i leave. thanks
 

·
Registered
Joined
·
1,806 Posts
i am having an inssue with my c4 atuo trans not engaging in gear and i can't figure it out. could it be the inner input shaft not fully inside the stall converter or would it only be a selector problem? i only have a couple weeks before i deploy and i have to have the car done before i leave. thanks
If you have no forward or reverse gears:
First check the oil level with the car idling in Park. It should be half way between the ADD and FULL mark. Check to make sure the linkage is adjusted properly. If the level is full then remove the rear cooler line and see if you have any flow (use a bucket - it should come out fast) If there is no flow then you have a bad pump. If you have oil flow but no gears then it MIGHT be that the converter you have (if it was just changed) is for a large input shaft and your transmission may have the small shaft if it is 69 or earlier. If that is the case then you will need to replace the torque converter with one for the earlier C4s.
 

·
Registered
Joined
·
80 Posts
Discussion Starter #30
Thanks GettingItFirst4!

I don’t let guys like that bother me. I needed a solution and when I found it on my own I felt compelled to share it. If my post helped someone else that makes me feel good. If my post “appalled” someone that is really their problem and not mine. If that guy really wanted to help someone, he would post some part numbers so the parts could be swapped instead of modified the way I did it. Until then, my way does work and it has been leak free for over three years now with no mechanical problems as a result of the modification. My wife drives it 30 miles to work and back a few times a month and can’t stop for gas without someone trying to buy it from her. Mission accomplished.

Thanks again,

Steve
 

·
Registered
Joined
·
1,806 Posts
Mmerlinn is a dealer of transmission parts and may have more parts knowledge than the four best C4 builders on this site - they definitely have more parts info than I do.
Using a shortened shaft could raise a few problems that may not be readily apparent - like wear on the case and poor fit with the manual valve.
Modifying the wrong parts may work but using the correct parts is alkways best.
Don't berate users - you may be cutting off more good information than you can get anywhere else.
Paul
 

·
Registered
Joined
·
80 Posts
Discussion Starter #32
Thank you for your insight Paul. Please allow me to respond.

Don't berate users - you may be cutting off more good information than you can get anywhere else.
This would be better advice for Mmerlinn. If you read every single reply to my post you will see that I never berated him but he did me. I believe I even referred to Mmerlinn as a “Very Skilled Technician” so if anything I complemented him. How did you get berate out of that? I never even once disagreed with him much less berate him. And what information did he provide? From where I stand he provided an opinion about my post but no real usable information about a C4.

Mmerlinn is a dealer of transmission parts and may have more parts knowledge than the four best C4 builders on this site - they definitely have more parts info than I do.
And yet why have we not heard from them? I posted this three years ago. I have no question that Mmerlinn and the four best have much more knowledge about a C4 than I do. I seldom talk much about my own qualifications because I am just here to help. I even qualified my solution and told people to take from it what they will. But since you brought it up, you should know I am an ASE certified master automobile technician and probably a little smarter than your average bear. I ended my automotive career on a high note as a Service Manager at a Chevrolet Dealership before moving to a better paying career. I got my start busting tires at a Firestone Store in early 70’s and went from there and I have worked in every bay. I don’t just rig things up and an automatic transmission is not much of a mystery to me regardless of brand and especially the shift linkage for heavens sake.

Using a shortened shaft could raise a few problems that may not be readily apparent - like wear on the case and poor fit with the manual valve. Modifying the wrong parts may work but using the correct parts is always best.
I couldn’t agree more and I would have loved to just get another shaft. I could have left my MIC’s in the tool box. That is why I was very careful about my assessment of the manual valve as discussed and photo documented in my post. I actually improved the fit of the manual valve.

I and the other members of this site are still waiting for those “correct” part numbers by the way. Just post those right on up here and I will ask the moderator to remove my post as I have obviously misled people.

No hard feeling and none taken,

Steve
 

·
Registered
Joined
·
50 Posts
So I had mine fixed a few weeks ago. An independent transmission guy came over and dropped the pan and valve body then removed the shift linkages and replaced the washers and reassembled making sure the shifter was working correctly. We tested by disconnecting the coil and cranking to see of the started would engage in Park.

Put the valve body and pan back on with a new gasket, replaced the fill tube gasket and I have had no leaks for about 3 weeks.

If I had worked on a transmission before I think I could have done this myself, but it was good to have a pro make sure the linkages were set up right when reassembling.
 

·
Registered
Joined
·
89 Posts
Love this thread! I will post here to save adding another thread. I am restoring my wife's 65 Coupe V8. We are replacing the engine so I pulled the transmission along with it. I am told it is a C4. Is there something on the housing to indicate what this transmission is all about? It was rebuilt in 1997 but only has a couple of thousand miles on it. Kids and life caused it to sit in her parents backyard for close to 15 years. We are back on track and have full restoration in sight.

Last year I had it driving and it seemed to shift fine. After removing it, it looks terrible. It is caked in dirty, thick, red stuff. I have confirmed that the power steering system has several leaks and am replacing / rebuilding all power steering parts and hoses.

Assuming that it is power steering fluid all over the housing and knowing that the transmission seems to operate fine, would you recommend anything for the transmission besides fluid change? After sitting that long, what unknown issues could be lurking? The transmission shop wants to open it up but I'm hesitant without some advice here. Also, the wiring from the transmission is in bad shape. Is that an easy job to do?

As I always end my posts, please feel free to educate or direct me in the proper direction if I am missing anything. I have no education in this but am having a blast with this project!

Thank You
 

·
Registered
Joined
·
1 Posts
Thanks for your informative post. I am working on a 66 Mustang and this post helped me determine that I had a guaranteed leak waiting for me. I am swapping in a new 302 engine and a TCI C4 that I got from Summit. The c4 comes with a universal style shifter lever bracket that slides on to the shift/manual shaft. It is intended for later model vehicles I guess, but the universal style shift shaft lever does not allow for the installation of the factory neutral safety switch. So, I ordered a new shift shaft/manual shaft from a Mustang catalog and installed it so that I could use the neutral safety switch. I installed that while I had the transmission on the bench, so it wasn't too bad but I would not want to do it under the car. I had a little trouble getting the internal throttle valve lever to line up properly when re-installing the valve body. Turns out there may be a reason I had difficulty.

I stumbled on this post trying to locate a new throttle shaft seal. I had to remove it a few times so I felt it would be a good idea to replace it even though it is new. I have the engine and transmission ready to install and was planning on doing that next. After reading your post I started wondering if the shift shaft I just installed was the same length as the one I removed. I did not replace the throttle shaft...just the shift shaft. I just went out an looked and sure enough, it is shorter. The throttle valve shaft is protruding too far out. I had not installed any linkage or the kick-down bracket that attaches to the shaft, so I had not noticed the difference yet. There is no way that the throttle valve seal will be properly seated because the there is a pretty big gap between the kick-down bracket that holds the seal in and the seal itself.

So I think my problem is the opposite of yours. My shift shaft is too short for the throttle shaft. Perhaps there are more than one length available for each as has been mentioned previously. However, like you mentioned, if this is the case then the information does not seem to be readily available. I don't know why Ford has to change everything a just a little, but who can keep track of all of it? Trying to get a flex plate with the right imbalance and the correct number of teeth to match the transmission that needs one of two different size bell-housings and getting the proper number of splines on the transmission input shaft and output shaft with the dipstick tube either in the case or in the pan.......I spend more time researching than working. I am not sure how I am going to proceed yet, but your post and this thread saved me a big headache next weekend.
 

·
Registered
Joined
·
67 Posts
Question

Great article but one question. Did you search for a o-ring with ID smaller to fit the threaded portion or are you saying that it makes no diff because it would still leak via the threads? If the later then all C4's should have transmission fluid on the ground when they were sitting on the lot brand new. This would have to assume the case seal was leaking also, wouldn't it? In your case you believe that the case seal was good so where did the fluid come from. I must be missing something.

My 65 FB leaks like a sieve and I was hoping to find a solution without dropping the pan, i.e smaller diameter O-ring.
 

·
Registered
Joined
·
409 Posts
Steve,
It is doubtful ( unless the trans is way over filled) that the vent tube would 'dump" fluid out. I will also say that later C4-5s had a "mushroom shaped" vent in the tailshaft housing so Ford may have changed the location for that reason.
Randy
 

·
Registered
Joined
·
44 Posts
Same Problem With Transmisson

I was just about to post a question pertaining to transmission leak on my 1968 Fastback with auto.trans. when I decided to check for others with similar problem. I am glad I did. I have had a seal job done on the trans., but the person who did the job must not know about the seal in question because after seal job it started to leak again, but from a different location. I could not located the leak, but I do know that leak was not from the prior location. I check where the trans. fluid was leaking from and i could not locate it. Here in Texas when it gets hot the trans. fluid leaks more. Now with the info I found here I will get someone with classic Mustang trans. experience to check and fix the annoying leak. I think that problem is the same as has been mentioned on the forum. Thanks for the info.
 

·
Registered
Joined
·
1 Posts
Looking for help on my 67 transmission

Hi Steve
I have the same problem on my 67 mustang that I just restored and the leak is driving me crazy I am going to have to try this to see if it will work with me. Do you have any other tips not mentioned in your article ? Also where r u located? thanks for the info.
could you email me [email protected]
 
21 - 40 of 41 Posts
Top