AOD Conversion

[Mister 4x4]

OK - so I've installed the AOD into my '71 behind the 351C-2V and have made the following observations. Hopefully someone else can use to help with their AOD conversion. I will add more information as I recall it.

Car Specs:

- 1971 H-code Mach 1

-- 351C-2V engine

-- FMX automatic

-- Ford 9" rear axle w/3.00:1 R&P

-- Hooker Competition Header (ceramic coated)

-- Pypes 2.5" stainless w/X-pipe

New transmission candidate

- 1989 AOD from 5.0L Mustang GT (with absolutely everything, except the slip-yoke, speedo cable, and fluid cooling lines)

-- shifter & cable

-- TV cable

-- wiring harness (neutral safety switch and back-up lights)

-- dipstick and tube

-- bell housing mounting bolts (longer than FMX mounting bolts)

-- torque converter

Parts purchased (so far):

- 28 oz flywheel from mid-'80s Crown Victoria (P/N: FRA-205 Pioneer Inc)

- Mr. Gasket flywheel bolts (P/N 6710)

- Aftermarket transmission crossmember (Ron Morris Tremec/AOD 67-73 - P/N: T5C4 from CJ Pony Parts) * not using it - doesn't quite fit right with headers

- AOD yoke (Rosehill Performance)

- U-Joint (conversion from AOD to Mustang driveshaft ... P/N coming soon)

- 1989 5.0 Mustang Starter (P/N coming soon)

So I pulled the engine and tranny out early on in Sep 2010, and I acquired the AOD by chance - so I was going to be putting the complete drive train in without any kind of recent, "well, that's how it was when I took it out" reference. I did discover that the overall length of the AOD and FMX are identical - bell housing to output shaft: 30.5" - meaning, the stock driveshaft should still work.

I put the AOD on a tranny jack and cleaned everything with Permatex Engine Degreaser Gel, power rinsed, took a wire brush to the nooks and crannies. Then I hit it with some Permatex Foaming Engine Degreaser to get it like this:

Once that was done, I installed the flex plate and discovered the flex plate bolts that came with the AOD were too long. Some new bolts did the trick, and I had the tranny in the car within a few minutes using the cool Ron Morris crossmember I bought from CJ Pony Parts:

The only problem is the weird way it fit in there - it kinda didn't. I was going to be happy with just letting it sit a little crooked, but once I installed the Hooker Headers, I discovered that the aftermarket crossmember was simply too big, and poorly designed for headers:

Since the collectors were hitting the crossmember, I had to come up with a new solution. I took the original FMX crossmember, cleaned it up and discovered that the pan on the AOD is bigger than the FMX's - that's the only difference in these trannies. So I notched the FMX crossmember, painted it, and installed it. Before I painted it, I put in between a couple of pipes and jumped up and down on it... if it can hold me at 6'5" & 300, it should do fine with the tranny:

Now the headers fit much better:

Afterward, I completed installing the exhaust system and began refurbishing the driveshaft. Removed the rust, painted, and installed new U-Joints. The front U-Joint is a conversion joint going between the stock driveshaft and AOD yoke.

The 'X-pipe' on the exhaust actually passes under the output shaft for the AOD (the red plug above the 'X-pipe'):

I'm still finishing up the nit-noids (cooling lines, shift cable routing, the TV cable, etc.), but so far it's in and seems to fit. I'll add more as it comes and fill in the blanks as necessary.

A couple of things noted along the line:

- stock '71 starter motor doesn't work with the '89 AOD. Traded it back to the parts house for a stock '89 Mustang 5.0 starter motor - fit like a glove.

- stock AOD shifter cable got pinched with the Ron Morris crossmember and rested on top of the header collector. I altered the shifter cable bracket to move the cable up higher, but now fits tight with the FMX crossmember (picture coming later)

- the dust boot on the end of the AOD is smooshed like an accordion against the AOD yoke mounted on the stock drive shaft. With the trannies both having the same overall length, I'm a little surprised by this. I will do more research to find out if I need to shorten the drive shaft a little (maybe an inch). Fortunately, the suspension does not cause the slip yoke to travel very much in or out of the transmission during cycling up and down on the lift.

- there are no AOD for '71-'73 Mustang cooling lines to be had anywhere. Based on first glance, I believe some stock FMX lines will work with some modification - more to come.

 

[caspianwendell]

Very informative great job Eric...thanks for sharing

 

[Totalled]

You sure you got a 28oz flexplate? 1981 and later 302s, including panther cars, were 50oz. A 164tooth big bell c4 application flexplate was used when my friend put an older motor in front of his AOD.

 

[Mister 4x4]

You sure you got a 28oz flexplate? 1981 and later 302s, including panther cars, were 50oz. A 164tooth big bell c4 application flexplate was used when my friend put an older motor in front of his AOD.

This is the P/N of the unit I bought from O'Reilly Auto Parts (seems pretty common among the vendors): Pioneer FRA-205

Thanks for asking though - I never turn down having another set of eyes 'checking my work.' Especially when stepping into unfamiliar waters.

Oh yeah - after seeing this picture, I'm reminded that this flywheel goes on in a specific orientation, making it possible for the AOD's torque converter drain plug to fit.

 

[machman_73]

Looks like your moving along nicely. ::goodjob:: Mark

 

[RacerX]

Love the pictures and the writeup. I'm doing the same in my convertible with 351 Cleveland and am not as far along as you. I'm swapping out a c6 though and my driveshaft is too short now.

 

[Totalled]

This is the P/N of the unit I bought from O'Reilly Auto Parts (seems pretty common among the vendors): Pioneer FRA-205

Thanks for asking though - I never turn down having another set of eyes 'checking my work.' Especially when stepping into unfamiliar waters.

Oh yeah - after seeing this picture, I'm reminded that this flywheel goes on in a specific orientation, making it possible for the AOD's torque converter drain plug to fit.

That's it. Interesting they sold it for that application though..

 

[TheJ]

Great work Eric, I'm glad you got the headers to work.

 

[TommyK]

You sure you got a 28oz flexplate? 1981 and later 302s, including panther cars, were 50oz. A 164tooth big bell c4 application flexplate was used when my friend put an older motor in front of his AOD.

This is the P/N of the unit I bought from O'Reilly Auto Parts (seems pretty common among the vendors): Pioneer FRA-205

Thanks for asking though - I never turn down having another set of eyes 'checking my work.' Especially when stepping into unfamiliar waters.

Oh yeah - after seeing this picture, I'm reminded that this flywheel goes on in a specific orientation, making it possible for the AOD's torque converter drain plug to fit.

Did you compare it to the FMX flex plate? I was always under the impression that the FMX flex plate would work on the AOD.

 

[Mister 4x4]

TommyK, I totally forgot about this thread. I did not compare the FMX plate to the new 28 oz plate I picked up... I didn't even think to. I actually have 2 spare plates now (the original FMX plate, and the one from the '89 GT - and can't really tell them apart).

Here's an update picture - the '89 AOD shifter is probably not going to work. Apparently, the tunnel in an '89 has a little bit of slope to it, hence the 'dung-beetle' look of the shifter bezel.

I recently re-installed my dash board, and it looks like the handle (in Park) is a little closer to where I think the radio will be than I'd like. So, the new plan is to go with a B&M Megashifter. More to come.

 

[mach71351c]

Eric I had a B&M Megashifter In my Grande and my buddy had one in his Z28 around the same time. We both had nothing but problems with the shifter falling apart. My buddy switched to a M21 4 speed and I switched to a B&M Quicksilver which never gave me any problems.

Mike.

 

[CZ-75]

This is a great thread. I want to do the same thing

 

[Don65Stang]

This IS a great thread. How'd the shifter turn out Eric?

 

[Mister 4x4]

The last picture I posted is how it stands. I haven't done anything with it as I got wrapped up in getting the dashboard back in this past weekend. I'll post a new pic of that (with the shifter), as well as bring in the center console for a test fit.

I'm learning toward the B&M Hammer Shifter. They have a lower-profile model for the '87-93 Mustangs w/AOD, that looks like it might fit better than the standard Hammer stand-alone plastic console.

Still doing research though.

 

[mustang7173]

Mister 4x4,

Here is a good website that has conversion kits, Early Mustang AOD Conversions-One important part is to have the AOD Selector Shaft and Arm installed so you can you your factory shifter. This will need to be installed before transmission is installed.

http://www.transmissioncenter.org/classic_mustang_to_aod_conversion.htm

mustang7173


Hello Mister 4x4,

After what I did to convert from FMX to AOD, I found this website that will let one convert to an electronic AOD transmission and install an electronic transmission controller.

Baumann Electronic Controls-

http://www.becontrols.com/index.htm

mustang7173

 

[cudak888]

There's got to be some way to get it to sit correctly - here's a '71 on Craigslist right now that seems to have the the Fox's AOD shifter jammed into a factory console:

-Kurt

 

[Mister 4x4]

I was inspired by Kurt's picture above ^^^, so I took apart the AOD shifter to see what I could come up with. I basically shortened the rear mounts (pop-riveted them back into place), put some spacers under the fronts, rubbed the white letters off the inside of the indicator lens (I'll put some stick-on white vinyl letters on the top - since they were out of alignment with the shift detents anyway) and stuffed it all back together. So far, so good!

Here's the shifter before modification:

And here's the [pretty much] finished product:

Also test-fitted the console, and it seems to be fine. Just gotta fine-tune the fitment after the carpet's installed - so nothing's permanent right now.

I guess this is the major hurdle to making this work. Now I just need to re-wire and adapt the AOD harness into the car's transmission harness so the neutral safety and reverse lock-out switches work again... then it should be all done.

 

[mach1000]

So did I miss if the original FMX flex plate would have worked? I'd like to do this conversion on one of my Mustangs at some point.

 

[Mister 4x4]

Yeah... sorry about that. I don't think I'll be pulling apart the whole thing just to find out for sure.

I will, however, check the bolt patterns between both the original AOD and FMX plates (I still have them)... but as for balancing, I don't know that I'll be able to tell unless there's some kind of stamping or something that denotes the balanced weight. I also don't believe there will be an access hole for the AOD's torque converters drain plug since FMX TCs don't have 'em.

Fortunately, the flexplate that I ordered (P/N listed earlier in the thread) is only $55 through a local O'Reilly Auto Parts store, and is typically in-stock.