Ford Mustang Forum banner

1965 Mustang Trans Swap

3K views 15 replies 11 participants last post by  Grimbrand 
#1 ·
Hello all,

I have a 1965 Ford Mustang with a 302 replacing the original 289 and a 4spd top loader. I got the car from my dad a few years ago, and despite my wife's attempts to teach me I just cannot drive stick. I am planning on swapping out the 4sp with a 1969 cruise o matic c4 transmission. I know this is sacrilege to some, but I want to be able to drive this car. I am keeping the 4spd just in case I sell it can go with it.

I was wondering a few things. Mainly, my mechanic thinks I might need a different size drive shaft. I know that I will need to change the yoke so that it will fit the C4, but can anyone tell me what # of splines I will need on the yoke, and also will i need a different size drive shaft?

Let me know when you can, and thank you for the help.

Anthony
1965 Mustang Convertible
302- 4spd
 
#2 ·
The C4 normally uses a 28 spline yoke, and as far as I know, so do all the small block Toploaders. It's possible that you have a 31 spline Toploader. But more likely, your mechanic was saying that your driveshaft might need to change length. This is something I would measure once you have the C4 in the car. Then you measure from the end of the output shaft to the face of the pinion yoke. Ideally, it should be 1/2-3/4" longer than the dimension from the center of the driveshaft's pinion u-joint to the cap of the transmission yoke.

Additionally, you'll also need to source either an external transmission cooler or a radiator with an integral cooler as well as run some lines. If you have a hot 302 that turns more than 4,000rpm, you may want to get a governor kit for the C4 that will give full throttle shifts at higher speeds, such as around 5,500 or 6,000. I would only recommend that if you have an upgraded valvetrain, however.

As for driving the car with a Toploader, is it difficulty in getting the clutch to engage properly? There could be some bad adjustment, or the Z-bar is bending, or the clutch is worn out, or the synchros just aren't working right. But props for wanting to actually drive the car and doing what you can to get that to happen!
 
#3 ·
What Paul said. =)

For what it's worth, the 4 speed Toploaders are a really good transmission. So are the C4's. Learning to drive a stick makes you feel like an idiot for a while, and it takes a lot of practice. It can't be easy having your wife try to teach you either! Without playing the "have you really thought this through?" thing (because obviously you have!) I do want to say that it would be worth putting the effort into learning, if you decided to get serious about driving a stick.

But if you just want to enjoy it and not go through that hard work, the old C4 is a joy to drive too.

Either way, I hope you have a lot of fun driving this old car, and welcome to AFM!
 
#4 ·
What Paul289 said...

CHECK THE LENGTH. The toploader and a C4 are probably different lengths. It's critical to get it right.

> Don't get rid of the toploader. Put it and everything that goes with it away and keep it.

> Since you plan to change everything, you might want to consider going with an AOD. I think you would like overdrive (4th gear).

CJM
 
#6 ·
AOD is unique in that it already has no torque converter action in 3rd and 4th gears. Because of this, a vehicle originally equipped with another auto (like C-4) has a numerically low rear axle ratio (2.69-3.10) which will "bog" using AOD, since the torque converter is not in play in 3rd and 4th. I found this when I put AOD in my '79 Ranchero. Installed a 3.50 gearset, ran beautifully! Not down-rating AOD, understand, it is a great choice!
 
#7 ·
Although if you're willing to change the rear gears an AOD can be an "okay" transmission, it'll never be a good transmission for cheap. They steal a lot more horsepower than a C4, and have a significant problem with their lockup torque converter. It is a mechanical setup, and gives you partial lockup in 3rd gear, with full lockup in Overdrive. Unfortunately, full-throttle shifts into 3rd and 4th will put things in a bind, and cause parts to either wear or shear to relieve the stress. It was a mediocre transmission for big soft shifting luxury cars, IMHO, and ill-suited to any performance application without a lot of work and expense.

I am not at all fond of the AOD's stock shift characteristics, the fact that it's about 50 lbs heavier than a C4, and I hate its fussy TV cable setup. It requires very careful calibration, and if the add on bits to your existing throttle setup don't work properly, it will burn up the transmission. To fix its shortcomings, typically the lockup converter must be sacrificed in favor of a one-piece input shaft, and a lot of upgrades that were included with the later 4R70W (the main parts generally fit inside an AOD just fine). The cost of these upgrades, done by a shop, is usually well over $2000.

All in all, I would rather have a C4 on any car over an AOD (given proper rear gearing for either). If you want an overdrive automatic, look towards the 4R70W. It is a descendant of the AOD, but gets rid of all the bad stuff, replacing its hydraulic guts with electronic actuators. It shifts asynchronously, which means it isn't dependent on multiple bits releasing and engaging at once to change gears. Instead, if you want first, it engages first. OD? BAM. And the lockup torque converter is actuated the same way. Typically, it is not programmed to lock the converter while in first gear, but can be programmed to engage or disengage any way you want, with most of the good controllers out there. It is much stronger and more reliable than a stock AOD, steals far less horsepower (comparable to a C4), and as long as you choose one built between '98-2001, has incredible longevity and power handling capability. V6 4R70Ws are still plentiful from those model years, and often need nothing at all but an aftermarket controller and rear gears to work perfectly for a long time, even if your car has a really potent engine.

Oh, and the "W" in 4R70W? Means "Wide" gearset. 1st and 2nd gears are a bit lower than a C4 or AOD, which means your car can really get up and move from a dead stop, making 3.73 rear gears feel more like 4.10s or so, without sacrificing mileage or top end capability at all.

Most people know that to use an overdrive transmission, you should change the rear gears to at least 3.50's or so. However, something that many people don't realize is that you should also use a lightweight (aluminum or carbon fiber) driveshaft if you put in an AOD or 4R70W. The reason for this is because the higher rotational speed of the driveshaft will cause significant driveline vibration. It can be hard on U-joints, as well as the tailshaft of the transmission and pinion bearings in your differential, not to mention being a constant annoying thrum while out on the highway doing 75+ mph. Since you will likely have to change out the driveshaft for a shorter one anyway, this is the time to invest a little more, and go with newer materials, which will not have the same harmonics. They also have resonant frequencies, but you'd have to probably be doing 300 mph for them to cause any trouble.
 
#8 ·
...I am not at all fond of the AOD's stock shift characteristics, the fact that it's about 50 lbs heavier than a C4, and I hate its fussy TV cable setup. It requires very careful calibration, and if the add on bits to your existing throttle setup don't work properly, it will burn up the transmission. To fix its shortcomings, typically the lockup converter must be sacrificed in favor of a one-piece input shaft, and a lot of upgrades that were included with the later 4R70W (the main parts generally fit inside an AOD just fine). The cost of these upgrades, done by a shop, is usually well over $2000...
I tried putting an AOD in my '78 Ranchero, and it worked for a little while until I burned up the direct drive drum. After that, I tried upgrading the clutch packs, and it never shifted right afterwards. So I put the old FMX back in it and it's worked fine ever since.
 
  • Like
Reactions: Grimbrand
#12 ·
"if you put in an AOD or 4R70W"?

AOD is mechanical, AODE and 4R70W are electronic. I have a 65 Mustang and am running an AODE. That is the close ratio version of the 4R70W. I am using a Baumman controller. The drive line is 1350 joints, 3.5 gear and 245-60-15. Two cross country trips in 2019 got me 12K miles. Very happy. If you are going to keep it and drive it over the road it is something for you to consider.
 
#13 ·
Hmmm could it be that this particular manual is more difficult? Perhaps if you could learn on a more modern manual it would be easier and you would gain more confidence. Unfortunately, I have yet to see a driving school that offers a class specifically on how to drive a manual. I used to have a 1984 S-10 5 speed manual which shifted ok. I test drove a brand new S-10 about a decade later and there was a huge difference. The newer model was so much easier. The shift throws were shorter and easier and the clutch was much lighter. It was almost as if I had to re-learn! Anyway, good luck in whatever you choose to do!
 
#14 ·
I swapped the other way, from a C4 to a toploader and my original driveshaft fit fine, yoke and all. The early toploaders had a 25 spline output shaft, if you have an original early '65 toploader you may still need a 28 spline yoke for an automatic. If you want an automatic, go with the C4. No sense in beating the hell out of the trans tunnel to make a junk modern transmission fit, IMO. With proper rear gears you can cruise on the highway with no problem. As far as learning to drive stick, what people don't tell you is that you need to learn to ride the 'bite point' of the clutch. It's not an on/off switch. Good luck with whatever you decide to do!
 
#16 ·
You save so much money by starting with a stock 4R70W, and not having to 'make the AOD better' that the cost of the controller is really a wash. And in the end, it's just a much better transmission anyway. Some guys seem to like the stock AOD, but I never could stand 'em.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top