Our 68 289 coupe is a father and son project. We are ready to tackle the leaking C4 transmission. But we would like to keep the car running while we do the rebuild - so I was considering buying another working C4 and installing it for the month (or more) it will take to tear the old one apart and put it back together.

What years C4 can I put in my 68? I found a rebuilt 65 and a 66. Will either of them bolt in with or without the bell housing?

 

Those years had the funky shift pattern. You don't want that.
Get one up to sometime in the late 70's or early 80's. I think 85 or 86 they went to AOD?

 

you should be able to put a '68 valve body in a 64-65 to correct the funky shift pattern. Also, the C4 has a 5/16 vent tube coming out the drivers side tail. I would recommend bending a new tube and raising it or extending it higher to prevent leaks. Also, take a look online, I believe there's another mustang or ford forum that has a thread dedicated to performance C4 builds. Good luck.

 

The main differences are where the dipstick goes and the valve body. They arent tough to rebuild, and most people who can assemble an engine should be able to rebuild a C4. If you screw up its just more work, provided you dont do something stupid like break the front pump. It took me about 3 hours to rebuild my 68 C4 for the Cougar, most of that was time spent cleaning parts. Pick up a book on rebuilding them, and there might be a few videos worth watching too. If you have a spare, you can DIY and learn from it.

So if you just want another one for it, as long as its a C4 it will bolt in with minimal hassle provided you have the right dipstick. input shaft splines changed and you really dont want a C3 or C5 trans. They look quite similar to C4s but have other things going on, as in the C5 is a lock up converter and the C3 is too light for a V8.

If you want to DIY I suppose I could send some info your way. Just drop me a PM and I will get some of it together. I really need my scanner working though..

 

Thanks for the help. We just hit the jackpot - found a C4 on Craigslist for $40! After some detective work, determined it is the twin brother of the unit in our car. We also got a rebuild kit and a video to get things started.

The "new" one looks to be in better shape than the original and may have been rebuilt sometime in the recent past. Planning a preliminary inspection of the "new" tranny and possible Dyno test at a local shop to see what we've got before deciding which one to rebuild and how far to go.

One more question - I read online about a mod to improve oil flow to one of the thrust washers - any advice on that one?