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C-4 65 Mustang Tranny Rebuild

3K views 12 replies 7 participants last post by  65Stanger 
#1 ·
I have been mulling over the site for a couple hours now, but cannot seem to find the information I'm looking for. If it is on here then please just link me to it, but if not it would be a nice addition for archives!

I have a 1965 Mustang 289 auto ... if you couldn't tell from my name!
She has the original automatic transmission on her which, for what I came up with on this website, is most likely a C-4.

She slips into 2nd and lags into gear. I want to rip off the tranny and rebuild it myself so I know what the problem is and that I fixed (plus I don't really trust people to work on my baby). I have experience with a manual clutch replacement on a 95 maxima, but this is my only transmission work. I am mechanically inclined and don't think (with the help of a good manual) the rebuild would be a problem.

Where can I find information (rebuild kits, rebuild manual, information on my tranny) I also wanted to know how easy it is to throw in a stall converter as I want to make that engine 300+ hp eventually. Should I just wait to install the converter when I need it or would it save me alot of trouble just doing it now. Also, how would that affect Horsepower and engine performance since it is just a stock 289 Hipo right now?

Thanks again guys ... BTW LOVE THIS SITE!!!
 
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#5 ·
The C4 is one of the easiest American auto trannys to rebuild. I've rebuilt and modified at least half a dozen now. But you do need good guidance. The Haynes Ford Automatic Transmission Overhaul book is a good one and the one I learned with. There are others.

Here is what I consider the Mother Site for info on modifying the C4 for performance, that also offers identification and differences through the years:

www.fordmuscle.com/forums/c4-transmissions/monster-c4-thread-text-edited-way-long-version2_9911.html
 
#6 ·
Thanks for the info so far guys!!! Keep it coming. I have another question about this rebuild after looking at another current thread along the same lines.


http://www.hotrodders.com/forum/c4-rebuild-using-transtar-87684.html

red65mustang said:
agree with Chazmac,

1965 C4= 289/225hp/300ft/lbs at the flywheel = biggest motor
197X C4= behind a few 460's !!!! as a factory option!

need to know what year and which motor will it be plugged into

65' 289=5 bolt bell housing, 65' 200=5 bolt, pain the butt

It seems as though the early C4, as in the one I have, is not cut out for more than 250 hp or so, but eventually I want to throw headers on it and a couple other things to try to get it up over 300 hp. The most I would ever think about running on this car/engine would be 300-350 hp.

Should I just consider trying to pull a C4 from a newer car at some junkyard and rebuild this one as it seems it would be much better suited for my application, or keep mine??? I don't think my car is all number matching anyway and its my first rebuild/restomod so I'm just trying to learn while transforming what I have into a beauty of my own! HELP PLEASE!!!
 
#7 ·
There are a few things you can do to the old C4's like yours, such as install later valve bodies, but if you are going to build up power, I wouldn't chance it. The best C4's I've used have been the '71 up units (I'd include 1970 bit some of these had a 26/26 input shaft and parts are getting scarce). Note that your '65 engine has a 5 bolt bellhousing pattern (the bolts that connect the bellhousing to the block-used in '64 and '65) so a later tranny won't bolt to your original engine. Later engines use a 6 bolt pattern. I don't remember for sure (I haven't done it) but I believe you can use the 5 bolt bellhousing on 6 bolt trannys. If that's wrong someone here will correct me.

The later C4's are pretty stout, and if well built can handle a lot of HP. See that C4 site I mentioned.
 
#8 ·
I've got a C4 in my Mustang, as well. =) I love the thing. Shifts beautifully, pulls good. I had the EXACT same problem as you, and I guess it happens every now and again. The shifter bracket/kickdown bracket has threads on the end that goes into the transmission, and after 40 years of cranking back and forth and being pulled at weird angles, especially if your kickdown is adjusted incorrectly, the threads crack. What happened was mine was in 1st gear, then it would shift HARD into second, and then slip all over the place. I tried everything. I eventually pulled it and rebuilt it with my boss's help (I work R&R at a tranny shop). If you need any help pulling her out, I can give you step by step instructions on doing it. Don't forget to disconnect the battery and all that stuff. Gotta pull the starter. It's a real easy pull compared to these new cars like 'Vettes and Mercedes. Basically make sure to check that bracket's threads. Also, you're gonna replace all your rubber seals and o-rings, right? =) You're going to be really happy with that transmission when it's all done, and you probably already love your 289. With a good overhaul kit and some clean guidance, your rebuild should go great. Also, are you thinking about replacing your torque converter? It's a good thing to do if you don't know for a fact that the one you have in there is in tip top shape.
 
#9 ·
Yes, I will probably just replace the torque converter! What would be the best way to go about getting a 7x C4 to replace mine? Also ... this project is on hold for 2-3 weeks becuase of money issues, but when I do it (whichever route I go) I will update it step by step with photos ... which section should I post that in?
 
#10 ·
hipo,
first de-code all of your car and check against the engine and tranny part #'s you have, so you know what you are dealing with

info for "how to" is in the knowledge base and on most mustang sites

unless your car was a museum piece till you bought it slim chance the motor and or the tranny are original,

post a new thread with the correct motor tranny info
 
#11 ·
Good luck

Replacing a clutch and rebuilding a trans are 2 completely different animals. I had one in my 66, loved it, and it is a bulletproof box. As for you problem, if it is not leaking, I would not yank it out untill I knew for a fact it had an internal failure issue. Change fluids, filter and modulator, and make the band adjustments. Then, if you are certain it is needed, take it to a PRO. It may cost a few hundred to have done, but it's money well spent versus opening it up and finding yourself as lost as working on a Klingon warp drive.

PS. : I am the second owner of my 66 and have had it for 30yrs. Before the recent project (351w upgrade), the c4 trans I had never required internal parts replaced.

Good luck
 
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