FMX swop for AOD

[Superbond]

Hey guys
I have been researching about doing a 72 FMX swop to a AOD.
I have a 351c in my 72 convertible. I have rebuilt the motor. Now a V4 with long header. I have 2:75 gears but plan to change to at least 3:30 and or up but no to crazy. She a cruiser not a racer. But I’d like to have a little more jam on take off. You know once in awhile. I’ll get rear end gear once I have the transmission in house.
Reading all those post on overdrive has me pea brain spinning! Back and forth, back and forth! What I do know is I don’t want a add on computer! Like I said it’s not a racer so I don’t need to upgrade the internals.
So
What I think I would be looking for is a transmission out of a 86-93. It takes a tv cable. But one of the things I don’t know is from what cars ( that will bolt up to my Cleveland) which cars are better the the other ( for internal gearing, out put shaft length).
Can I use my own flex plate and yoke?
What I’ll need for my floor shifter to hookup to the new transmission and how do I get the reverse and neutral switch to work as it should. And if there’s anything I’m forgetting let me know. Thanks

 

[Superbond]

so
I take it there’s no one out there that has done this application that I am looking to do.
I know this will take me time to find the proper transmission and Ford 9” gears (3:30 up to 3:70).
If anyone has used one of these 86-93 AOD and have some input for me. Please help me out as this is a big decision and I don’t want to have to redo it because of the wrong information.
Anyone has or know where I can find these things I’m looking for and would like to sell them I would be interested in them.
I have a budget and I wish it was a whole lot more. But it’s not. That is why I’m looking for all the information and help from you all.
Thanks for your time

 

[Don C]

I have some miscellaneous notes for AOD conversions.
The best ones are out of V8 pickups, then V8 cars, then V6 cars.
For carbureted vehicles they need to be pre-1986, so they have the right setup for kickdown linkage.
Get the yoke with the transmission, it will connect to your existing driveshaft. The AOD and FMX lengths are within 1/8" pf each other.
The balance changed between 1981 and 1982, from 28.2 oz. to 50 oz., so the flexplate for your engine needs to be a 28.2 version.
Also, you need the AOD torque converter, so may as well get the flexplate, if it's 1981 or older, and block plate that goes with it. From what I see a C4 28.2 oz. flexplate will work, not sure about FMX.
The AOD requires longer bell housing to engine block bolts.

 

[Sheriff41]

I used an AOD out of an 86 Mustang 5.0L AND it works fine. The full size car and truck AODs have a different governor and stall to compensate for the weight of the vehicle and would be better. The later model AOD the better. Ford made improvements over the years.

I had 3.25:1 gears and the engine never seemed to get into the power band. I changed to a 3.89:1 and it really came to life. When running on the highway the RPMs are close to when I had the C6 and 3.25s, but a lot more fun off the line! I'd recommend a 3.50:1 to 3.70:1 ratio, though.

 

[Mister 4x4]

My AOD is from an '89 5.0. Everything that Don C said is truth. I have factory 3.00s in my '71, and the '89 5.0 came with 2.75s, so it's doing quite well, actually. 3.25s or 3.54s would definitely wake up the bottom end, but top-end cruising speed rpms will start creeping up as well.

Mine also came complete, minus the yoke - which I found online. Picked up the 28oz flex plate at O'Reilly's, along with some new flex plate bolts and TC bolts. The TV cable and shifter came with it as well (minus the throttle bracket - he needed those parts for his T-5). The TV cable didn't need any adjustment - as long as there's no slack in the cable, it'll be fine (too tight, it'll shift early... too loose, it'll shift late). Very easy conversion.

 

[Superbond]

I used an AOD out of an 86 Mustang 5.0L AND it works fine. The full size car and truck AODs have a different governor and stall to compensate for the weight of the vehicle and would be better. The later model AOD the better. Ford made improvements over the years.

I had 3.25:1 gears and the engine never seemed to get into the power band. I changed to a 3.89:1 and it really came to life. When running on the highway the RPMs are close to when I had the C6 and 3.25s, but a lot more fun off the line! I'd recommend a 3.50:1 to 3.70:1 ratio, though.

If you used that transmission from the mustang. You must have had to buy a computer to operate it no?
And you think the 3:70’s that lucky number!

 

[Superbond]

I have some miscellaneous notes for AOD conversions.
The best ones are out of V8 pickups, then V8 cars, then V6 cars.
For carbureted vehicles they need to be pre-1986, so they have the right setup for kickdown linkage.
Get the yoke with the transmission, it will connect to your existing driveshaft. The AOD and FMX lengths are within 1/8" pf each other.
The balance changed between 1981 and 1982, from 28.2 oz. to 50 oz., so the flexplate for your engine needs to be a 28.2 version.
Also, you need the AOD torque converter, so may as well get the flexplate, if it's 1981 or older, and block plate that goes with it. From what I see a C4 28.2 oz. flexplate will work, not sure about FMX.
The AOD requires longer bell housing to engine block bolts.

You say pre 86 For carbureted ? Why is that?
So 86-93 like I thought wouldn’t be for me as my car is carbureted.

 

[Superbond]

My AOD is from an '89 5.0. Everything that Don C said is truth. I have factory 3.00s in my '71, and the '89 5.0 came with 2.75s, so it's doing quite well, actually. 3.25s or 3.54s would definitely wake up the bottom end, but top-end cruising speed rpms will start creeping up as well.

Mine also came complete, minus the yoke - which I found online. Picked up the 28oz flex plate at O'Reilly's, along with some new flex plate bolts and TC bolts. The TV cable and shifter came with it as well (minus the throttle bracket - he needed those parts for his T-5). The TV cable didn't need any adjustment - as long as there's no slack in the cable, it'll be fine (too tight, it'll shift early... too loose, it'll shift late). Very easy conversion.

What motor do you have and is it fuel injection?

 

[Don C]

Mister 4x4 said his came from an '89 with a TV cable. At some point the cable was done away with and handled electronically by the EFI controller. As long as your transmission has the provision for a TV (kickdown) cable you will be OK.

If you used that transmission from the mustang. You must have had to buy a computer to operate it no?
And you think the 3:70’s that lucky number!

I believe the computer controlled AODEs came out in 1991.

 

[mrgmhale]

I have performed an AOD transplant in our 1973 Mach 1, which originally had a C4 in it. Many of the steps are going to be similar to an FMX replacement. But, the FMX aspect of your transplant may not be identical, in fact I am certain you will come across some nuances where our projects will differ. One part of the transplant involved adapting the Neutral Safety/Backup Lamp Switch wiring from the harness used for the C4, where I had to spice the old harness wiring into a new AOD Neutral Safety/Backup Lamp Switch harness. The splicing was not difficult, or even that tedious. But it had to be done. Below are some YouTube Video links I posted for anyone interested in doing an AOD transplant into a Mustang. I feel that the videos can't do anything but help you (and others) be better prepared for the task when you undertake it. As for the Parts List and Vendor List for our transplant, this is where you will be in a little different territory than I was, as you are swapping out from an FMX tranny. Hopefully you can come across info specific to the FMX being replaced from someone who has been there.



Following is a list of relevant YouTube video links contained in this document’s prior paragraphs, and from YouTube listings. Attached is a file with a brief description of what each video covers.







https://youtu.be/vdR-z3KV0UE
https://youtu.be/YCBBgd-olQ0
https://youtu.be/NcYr68atRjM
https://youtu.be/iFNXTGXNNcQ
https://youtu.be/2tTwnbcZZkY
https://youtu.be/8QncIKQTvNo
https://youtu.be/b4lnPReGWuM
https://youtu.be/zfYe--Gsjdk


Setting up Throttle Valve Pressure from the carburetor cabling:

https://youtu.be/KYIAqqYUKNo

I acquired our AOD from Monster Transmissions, as they were recommended, and they had an AOD transplant kit already configured. We did run into an assembly issue, but in the end Monster did provide some assistance to help me offset some added expense I ran into due to an error on their part. I am pleased with how the project turned out, and the Monster AOD is performing properly.

As for how I feel about having done the transplant... We have a 3.5:1 TractionLok rear axle gear set (prior owner replaced the factory 2.79:1 rear axle gears with the TractionLok unit). At 60 MPH the engine RPM in the C4's 3rd gear was just under 3,000 RPM. That was not as bad as us having a 4.11:1 set of gears at that road speed, but it was a high enough RPM to make it difficult to enjoy driving it at highway speeds for more than 15 minutes. After installing the AOD the engine RPM at 60 MPH is now just under 2,000 RPM, and our top speed is no doubt higher, since the engine (a street/strip 351W, not "C") has enough torque to overcome the increased air resistance at the higher speeds of the Mach 1. The 351Cs when built can wind up at higher RPM levels than the 351Ws with the outrageous "C" porting. But, the 351W is more adept for street driving, where we need lower RPM torque to scoot around on the public roadways. The modest 360HP at the crankshaft translates into has sufficient torque to handle the wind resistance encountered at higher speeds (100+ MPH). It does not pin me into the seat at Wide Open Throttle quite as much as our 1969 Shelby GT500 does, much less the even more capable 2020 Shelby GT500 we have. But, Mach 1 with the AOD tranny can still hold its own.

If you have any specific questions please feel free to post them in this thread, or you can email me at [email protected]

Have fun with the AOD project! I certainly did, and I am very happy with the outcome.

 

[clevelandcoupe]

Just another piece of info from my installation of an AOD in my Model A. The lokar kick down cable assembly is very accommodating for our cars if you do not utilize the factory cable. I agree with Mister 4x4 that a tight cable is better than a loose one, but too tight in my application would not always let the trans shift all the way to low gear without completely stopping first. I am very pleased with my installation with over 50,000 miles.....
Thanks, Jay

 

[Fabrice]

Did my FMX to AOD 2 months ago.
Regarding safety switch/reverse light, I first prepped the swap and had the connector on the AOD ready. Had all the circuits doc ready and was planning to do this on site during install.
The reason you want to do this is because the travel distance of shift linkage via the shifter is greater on the FMX.
But once I saw how that was, decided it wasn't necessary at all.
Instead of touching my harness, using basic math and the lever dimensions, I've projected the travel distance of the AOD linkage onto the pivot point of the shifter and modified the lever pivot point by relocating it (31 mm higher in my case).
As a result after little easy welding/fab, the dial inside the car is exactly matching the AOD gears position. While if you do not, not only you need to modify your harness, you also can't use your original shifter.




The FMX support, including the rubber/hardware, can also be reused with simple cut.
I have made a simple inspection temp plate. As soon as the weather permits, I'll make a new one and remove the support to reinforce it a tad/give it a nicer finish.



For the install, I had to remove one header, as I had just removed the driver side one for EFI reasons a few weeks earlier, I removed the passenger side, but during install, I had to cut a ear of the AOD casing, +-1.5 cm/bits more than 1/2 inch as otherwise it wasn't possible to align/insert the trans into the engine guides and bolt it. ( @Don C is right, you need longer bell housing bolts. Do not order the ARP bolt kit supposed to be for this, it doesn't )



One thing I regret is to have trusted Lokar for their dedicated kit. Not only the hardware they provide is useless and ended up fab all and kept only their cable and spring. Turns out the spring isn't right. It's on the weak side to push the lever back to zero position. So, there too, i'll be addressing this by replacing it with a proper spring. So if you can lay your hands on better cable, like OEM, do that. This lokar thingy is not to be trusted and certainly not worth the money.



Also make sure your trans has its shifter up (if you keep the original shifter).

I have used a Hugues 2500 stall converter, running 3:50 gears, and while it's perfect on highway, cruising in 1600-2000 range
I think 3.55 would be a better choice for overall, as I find myself using it more around and in town in third, as the rpm are real low when the 4th kicks in, just above idle.

Other details I did, was to use braided teflon lines to replace the original metal lines and make a new bracket for the TV and Throttle cables to have them really operating together. The tension of the TV cable being important on this particular trans.
The bracket (up side down on the pict) is now a one piece aluminium and both cables are in line & sync.



Happy swap!!

 

[Sheriff41]

If you used that transmission from the mustang. You must have had to buy a computer to operate it no?
And you think the 3:70’s that lucky number!

Nope. The AOD uses the TV to control shifts. I made my TV cable using some home made brackets and a lawn mower throttle cable. Works great and is much cheaper than the aftermarket kits. The later AODE would require a computer. It is important with the AOD to set the fluid pressure correctly. I recommend getting a pressure gauge and doing it by the book. It is easy to do and the gauge is inexpensive.

On the gearing, you have to get what you like and what your engine was built for. In my case, the Q-code engine comes on strong in mid-range RPMs so I went with the 3:89s. If you look on some of the Fox-body Mustang forums you'll find the 3.73 gear was favored for AOD cars and 3.55s for the 5-speed cars.

 

[Bobby]

I'm doing the same for my 72 Mach 1. I debated on whether to convert to a 4 speed Top Loader but as I added costs up, it was in excess of $7K so I chose the AOD. I found a vendor on eBay that will sell you the package deal. AOD tranny, flex plate, torque converter, cover plate plus many extras for $2300 plus $250 shipping and, unfortunately, a core charge. They would not accept my C6 as core so whatever you have, you'll have to sell separately. They are available for tech questions and pre-sale questions. You can request to delete some items that you may already have to lower the price. Check it out on the link. https://www.ebay.com/itm/222270810029?hash=item33c05f67ad:g:9JwAAOSwiYFXLfJh

You would also need to purchase separately a AOD shift link conversion kit and an AOD tranny mount for the 71-73.

 

[Fabrice]

Note also you you can do this for even cheaper. I had access to a used AOD, and with parts and guidance from Ken at badshoeproductions.com
With his full rebuild kit + tools (o-rings L shaped compressors required for 2 clutches) + new converter, it costed me just over a €1000/$1150. (thats including shipping to Europe and import taxes)
You can't go wrong with Ken's support really.

I did reuse the original flex 164 tooth plate which is also 28oz with an FMX.

The only necessary parts to match the original were a yoke from Sonnax (picked this one because it was having the same size for the the u-joint as my 73 shaft (easy to find u-joint in the future as they are the same as the original 73)

For the TV cable, the only thing that matters is that your cable must have no slack & no tension when the lever is at this rest position and ensure the cable is sync with the throttle. Unless the trans is faulty, you have zero pressure when at rest position. The lever inside the trans can't push the TV valve open on the body unless the return spring is faulty or wasn't installed properly.
So it's a matter of geometry and spring.
At rest while engine idles, the lever must be at the rest position fully and the pivot point on the throttle body must be ex-center just enough so that when you are full throttle that the TV lever reaches also most of its travel ( the valve has open the high pressure circuit in the trans fully way before its full travel is reached, so no worries if not 100% open when FT). If not enough, you know you need to offset on the throttle linkage more. If too much, you will not be able to have full throttle as the TV cable will be at max tension before the rotation is complete.

Here a good example of wrong TV cable adjustment on both trans and throttle body (and how to fix it) and with pressure tests
https://www.motortrend.com/how-to/hot-rod-rescue-adjusting-aod-tv-valve-shift-timing/
Here one of his vid on the TV cable.. Which is basically only what you need to do if you are sure that the geometry is correct.

 

[Mister 4x4]

What motor do you have and is it fuel injection?

I have a 351C2V w/an Edelbrock 1406 4bbl, but soon to be replaced with an Edelbrock E-Street TBI. I used a Holley throttle linkage bracket for the TV cable, though, which should still be fine for the E-Street.

Fabrice is correct on the TV Cable tension - no slack, and no pre-load. When they were set up from the factory, the installer placed the throttle end on the throttle, ensured there was no tension on the cable, and locked it down. A lot of people say you need to use a pressure gauge to make sure it reads something like 27psi on a tuner port on the transmission, but setting it with no tension/no slack pretty much does the same thing.

Others talk about getting high stall torque converters (something to do with the lock-out rpms), but I used the factory TC and have had zero issues with any lock-out weirdness (the factory lock-out is something like 1800, and the high performance folks swear you need at least 2200, which is simply not true unless you're planning on racing it). Mine's just a cruiser and car show entry for the most part, so my needs are a lot less than the speed demons. My engine puts out around 400 at the crank, and has no issues giving me a solid burn-out even with the 3.00 cruiser gears it came with in 1971. Hey, if the Fox-body factory 3.00s (2.75s for the 'verts) had no issues smoking Camaros and Firebirds from back in the day, who am I to second-guess that? LOL!

 

[mrgmhale]

Just another piece of info from my installation of an AOD in my Model A. The lokar kick down cable assembly is very accommodating for our cars if you do not utilize the factory cable. I agree with Mister 4x4 that a tight cable is better than a loose one, but too tight in my application would not always let the trans shift all the way to low gear without completely stopping first. I am very pleased with my installation with over 50,000 miles.....
Thanks, Jay

I am happy to see there are a few other AOD fans that also realize that higher Throttle Valve pressure over the factory spec (30-35 PSI) is not harmful, whereas inadequate pressure will lead to incurring damage to the AOD. I set our AOD up with 39 PSI, as it increases the road speed at which the 1-2 and 2-3 upshifts occur. Our setting is just a bit higher than the factory spec, but I was not willing to go much higher as too much of a good thing might become obnoxious or troublesome in having a tranny that shifts a bit more harshly than what I want. Increasing the speeds a little but for the upshift points is one thing, but having upshifts that are so harsh that they will knock the teeth out of my head is quite another.

For anyone wanting to see how to properly set the Throttle Valve pressure at the carburetor for an AOD equipped car I have two YouTube videos Lynda and I created and posted on YouTube. The 2nd video shows a bit more detail than the first video:

 

[Fabrice]

I mentioned using 3.55 while @Sheriff41 said: "If you look on some of the Fox-body Mustang forums you'll find the 3.73 gear was favored for AOD cars and 3.55s for the 5-speed cars."

He is right, 3.73 would be more fun en still ok rpms at 100mph

BUT dang it, I live in the Netherlands!
Scroll down to the very end of all countries and you will understand more easy why I prefer slightly lower gears.. :O

https://www.globalpetrolprices.com/gasoline_prices/

 

[1973grandeklar]

My understanding is that the AOD has the similar gear train design as the FMX. It is a Ravigneaux planetary gearset. So the transmission should be highly compatible as an upgrade? I understand the cases are different, the lock up thing is AOD, and the TV cable use. But what else is different between the FMX and AOD. The FMX was listed for light duty, is the AOD beefed up?
I ask because my 73 Grande has a C6 and will be getting a Q code 351C (using the 72 Mach 1 engine) with a Sniper system on top. But I have the flex plate from a 302 with an FMX. Flex plate is like new. I have an AOD from an 85 F-150 laying around as well (no flex plate). Seems this might be a good path forward instead of rebuilding a C6, rebuild the AOD and install? I will be using a Holley TBI so adding TV cable should be straight forward.
Also I seen mention of the neutral safety and reverse switch? Cannot use the 1973 OEM switch from C6? Splice into the OEM switch on the AOD?

 

[Fabrice]

@1973grandeklar, I have detailed above the neutral safety/switch.
The thing is, the travel distance of the lever on the trans is shorter on most AOD's, so you can do as I did, move the pivot point higher on the shifter arm. There is then match on the dial inside, and no need to modify anything on the harness.
Or if you want, you can use the all in one safety switch/reverse plug on the trans and hook it to your harness.

Another option, is to modify the transmission lever so it has the exact same length as the previously installed trans and shifter/electrics will work as well. But as I've found out, the levers are extremely hard. They have a heat treatment that makes basic modification really tough. I have spend hours modifying the TV lever just to have it aligned to the cable to not get any chances of cable wear and oh boy did that thing fought hard!! The shifter arm isn't hardened, so it was easy pizy.

Yes, the FMX is the grand mother of the AOD. They indeed share the same Ravignaux planetary.
The AOD can take punishment for sure but has 2 flaws in its design ( that can be easily fixed ).
- The first is the snap ring used on the first clutch after the pump, its the reverse on top of my head, but it turns depending on gears you're in, and centrifugal forces can force that ring to open and it then release the "sandwich" of that clutch.
I've used a Sonnax incapsulated snap ring (2 pieces vs one) replacement for that. I have somewhere the ref number if you need it.
(top left on pict).

- the inner shaft, is thin, and on "hard" downshift it moves back and forth and can on pre 89 AOD's with cast drums (90-93 have light weight iron drums), slam the shaft into the clutch splines. At some point if it comes a bit too deep, it will close an oil passage.
So here you have 2 options. You can fix as I did, let machined a small groove, add a ring that prevents the play, and additionally create extra oil passages on the drum (top right on pict).
Or like some do, replace the shaft by a stronger one, which in my opinion is BS as this doesn't address the faulty design and would also mean change the drum too.
That is in case of a lock converter. If you plan non lock, then if your converter has high stall, then yes, you need a stronger shaft as de converter multiplication applies loads of torque on that thin shaft, You'd still should had that ring to the new shaft. On non lock cases, always add a trans cooler no matter what.



The flex plate can be reused only if 28oz.

All the mods above are all present in all the AOD's you'll find in speed shops. TCI Streetfighters, monster trans etc..
But if you plan a non lock converter and the trans is in its juice. If your right foot is heavy, you may have problems at some point...