FMX swop for AOD

[Superbond]

And as everyone says the newer the transmission the better it is up to 92

 

[vintageman]

Thanks Superbond, this helps a lot.

Tom

 

[Superbond]

Your welcome. I hope it helps you as I am in the same situation as you. Trying to find the best donor transmission

 

[Superbond]

I'm still looking for my donor Transmission. Down to a 88 mercury Marquis( don't know the milage or what the motor its bolted up to yet. It is berried under snow right now) and or a 92 Mercury Cougar that has 73k which was bolted up to a 302.
The one thing I never really thought a bout was my speedometer cable hookup. how will that work on these newer Transmissions?
Top

 

[Fabrice]

Exactly like the old one. Tho, there are AOD’s with different grooves in governor being machined and in these rare cases you’d need a gear that fits these.

 

[Superbond]

but I can still use my original speedometer cable. Just change the plastic gear at the end?

 

[Sheriff41]

but I can still use my original speedometer cable. Just change the plastic gear at the end?

Yep, I did on my C6-to-AOD swap.

 

[Superbond]

thanks
Good to know

 

[MaddMike]

This thread has a lot of good info. But I am seeking some advice. I have an FMX and it runs just fine. Our highway speed limit here is 81 MPH (130 KmPH) after 70 MPH I get a slight rhythmic vibration like something is very slightly out of balance, perhaps the drive shaft. But the trans is good and dependable. When I restored the car I rebuilt the 351C from the crankshaft so it was complete. With the FMX I cleaned and did a rudimentary rebuilt of the valve body and added a Transgo shift kit. It runs good and is snappy.

But on the highway with a 9" 3:25 gear the RPMS are up there and it eats gas over 60 MPH as you'd expect from a '71 motor produced when gas was .30 per gallon - I am getting about 14 1/2 MPG on the highway. I was considering swapping the FMX for an AOD trans. But considering the FMX runs fine - how much of a benefit or upgrade would an AOD be for me? Would it save much gas, I live in Europe where we're paying $6.00+ per gallon (36 CZK per litre)? Is the AOD as sturdy as an FMX and would I get much more if any, added to the top-end. It takes off nicely BTW but with the set up I have, top end isn't much over 100 although I have rarely ever taken it that high.

I would appreciate opinions - not from those who "think" they know or have a friend of a friend but from those who have experience with this topic?

Thanks!

 

[Sheriff41]

With an AOD and 3.25 gears my 351C 4V routinely got around 20 mpg cruising at 70 mph. I have had no negative experiences with my AOD for the 20 years I've had it in the car. If I were to do it today I would seriously consider the 4R70W over the AOD for the more robust internals and electronic controls.

 

[Hemikiller]

There's a lot to cover on this.

Vibration - most likely suspects are your u-joints, but you could also have a worn extension housing bushing in the FMX, or the pinion bearings in the 9" are on their way out. Less likely is tire balance or rear axle bearings.

Assuming you have the logistics of getting an AOD to you covered, it's a worthwhile swap. They will require a controller, but it allows you to tailor the transmission to your tastes quite easily. The AOD is known to be a bit "wonky" in it's shifting, and very sensitive to the TV cable settings. IMO, the early TV cable AODs are getting scarce, yet the later 4R70Ws are still quite plentiful and cheap, which makes them a better candidate. The stronger internals are bonus.

My 71 XR7 has 3.50 gears with 26" tires, it cruises at 2250 at 75mph. I haven't finished a full tank yet this year, but I anticipate mileage in the high-teens on a mild 2V headed 351C.

 

[MaddMike]

With an AOD and 3.25 gears my 351C 4V routinely got around 20 mpg cruising at 70 mph. I have had no negative experiences with my AOD for the 20 years I've had it in the car. If I were to do it today I would seriously consider the 4R70W over the AOD for the more robust internals and electronic controls.

Thank you very much it has been helpful

 

[MaddMike]

There's a lot to cover on this.

Vibration - most likely suspects are your u-joints, but you could also have a worn extension housing bushing in the FMX, or the pinion bearings in the 9" are on their way out. Less likely is tire balance or rear axle bearings.

Assuming you have the logistics of getting an AOD to you covered, it's a worthwhile swap. They will require a controller, but it allows you to tailor the transmission to your tastes quite easily. The AOD is known to be a bit "wonky" in it's shifting, and very sensitive to the TV cable settings. IMO, the early TV cable AODs are getting scarce, yet the later 4R70Ws are still quite plentiful and cheap, which makes them a better candidate. The stronger internals are bonus.

My 71 XR7 has 3.50 gears with 26" tires, it cruises at 2250 at 75mph. I haven't finished a full tank yet this year, but I anticipate mileage in the high-teens on a mild 2V headed 351C.

Thanks for the info and regarding the vibes, the rear end is all new when I restored the car. so will look to the U-joints and housing bushing. Thank you.

 

[mrgmhale]

With an AOD and 3.25 gears my 351C 4V routinely got around 20 mpg cruising at 70 mph. I have had no negative experiences with my AOD for the 20 years I've had it in the car. If I were to do it today I would seriously consider the 4R70W over the AOD for the more robust internals and electronic controls.

We went aod 2 1/2 years ago on our 73 mach 1 with 3.5:1 tractionlok rear axle gears. I have not measured fuel consumption rate. But performance at lower speeds plus comfort with 1,800 rpm at 60 mph is nice. Cruising at higher speeds is still nice. Street/engine has plenty of power to overcome air resistance at ”higher” speeds. I wish only that I had gone 4r70w also, just for convenience of tuning up shift speeds more easily. Live, learn. No regrets Re going aod.

 

[MaddMike]

We went aod 2 1/2 years ago on our 73 mach 1 with 3.5:1 tractionlok rear axle gears. I have measured fuel consumption rate. But performance at lower speeds plus comfort with 1,800 rpm at 60 mph is nice. Cruising at higher speeds is still nice. Street/engine has plenty of power to overcome air resistance at ”higher” speeds. I wish only that I had gone 4r70w also, just for convenience of tuning up shift speeds more easily. Live, learn. No regrets Re going aod.

Noted. I see the pattern of support for the 4r70w. Thanks

 

[MaddMike]

I appreciate the comments. Is there any issue bolting up a 4r70w to a 351C and what about the shifter, can I use my original shifter? I assume yes if others have done it but just looking for any additional comments.

 

[Sheriff41]

I appreciate the comments. Is there any issue bolting up a 4r70w to a 351C and what about the shifter, can I use my original shifter? I assume yes if others have done it but just looking for any additional comments.

From https://7173mustangs.com/threads/4r70w-current-day-swap-info.34967/page-2

 

[Sheriff41]

This one has some good info, too: https://7173mustangs.com/threads/up-grading-to-a-aode-4r70w.40129/#post-417889

 

[Superbond]

just an update
I bought a AOD out of a 91 Crown Vic. Had a transmission mechanic go thought it and said it was like new. He changed some seals and o-rings,gaskets. I installed it and added the Lokar TV cable and the adapter at the carb. work great! my speedometer is correct now .All is good

 

[BUCKWHEAT]

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.

I put a (non-electric) AOD from a 1980 F-150 into my 1967 302 4V C-4 Mustang. Key is the kick-down rod from carb to tranny. Worked great. 3.50 gears work OK. I would pick 3.7's personally.