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FMX to AOD swap. Complete report.


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Mike, I am thinking 3.8 since the max limit in Au is 110 kmh (approx 68 mph)

So basically, quick maths ....mumble, mumble, carry the 2, = 17% higher revs. So instead of 2000, I'll be doing 2340 revs.

Is this too much for long cruises, guys, with your experience? Versus 2150 revs going to 3.5 from 3.25 gears.

 

I used to run 2500 on the freeway, 15k a year. I never had an issue with it, but I ran stock exhaust.

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That's the question you need to answer for yourself and it mostly depends on your driving conditions. As mine sees lots and lots of freeway use I wish I had gone with a 3.55:1 instead of a 3.8:1.

The increase in acceleration from the original 3.0:1 to the 3.8:1 is way smaller than I had expected. Still the car feels much more balanced now, lighter and livelier and that is a big plus.

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Mike
"If I were you...... I´d rather be me." 😛
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65 mph? 3.8 definitely.

You'll never rev higher than say 2500-2700.

I did not do any actual math for those numbers but it's just what I remember from mine approximately.

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Mike
"If I were you...... I´d rather be me." 😛
Check out my video:
http://www.7173mustangs.com/thread-my-mustang-in-action

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if you still did mainly highway driving Mike, but the max was 65mph, would you go the 3.8? Or still the 3.5 in hindsight.

 

I also agree with using the 3.8 with your speed limits. I think you'll be quite happy with the results.

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As mine sees lots and lots of freeway use I wish I had gone with a 3.55:1 instead of a 3.8:1.

The increase in acceleration from the original 3.0:1 to the 3.8:1 is way smaller than I had expected. Still the car feels much more balanced now, lighter and livelier and that is a big plus.

 

How bad was the acceleration rate between the FMX and AOD with the 3.00 gears? I ask because there shouldn't have been a noticeable difference, since the FMX and AOD are purported to have the same internal gear ratios (with the exception of the AOD having the OD).

 

My thoughts on this are that the 5.0 Mustangs with AODs came with either 2.75 or 3.00 rear gears as well... and they didn't exactly suck performance-wise in their day (now, "in reality compared to present-day," that's a different story). This is also why I tend to disagree with the mindset of using higher stall converters than what came stock with the AOD for 'normal' driving - Ford knew what it was doing when it matched up those components, after all.

 

I'm also interested to hear more of what Doc has to say about his experience in souping up his engine, because I actually went along a similar line as he did, so I'm essentially sitting on a blend of his engine build mated up with your AOD experience (prior to changing your rear gears). Based on the 150+hp gain CompCams says I should expect, and the 3.00 gears, I'm hoping to see some decent gas mileage along with the horsepower/torque increase overcoming the tall gears for a burn-out and some "Smoked Rice" every now and then. ;)

 

Again, this is all just me speculating, since I haven't actually driven mine any further than from the trailer to the garage and back, so I honestly have no idea if I have a monster or a turd at this point. :chin:

Eric

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Yeah but still with the same gear ratios the AOD feels little lamer than the FMX. I guess it produces more parasitic drag but the main difference is the AODs silly habit of almost ignoring second gear. It goes into third very early and thus the car feels slower.

This situation improved after some fine tuning of the TV cable but it's still present and noticeable. There are aftermarket valve bodies that specifically address that issue.

But if you try to tune your shift points as high as you can you can make up for it to some extend.

Anyway, with high shift points and 3.8 reads my car now feels pretty good and well balanced. Not anywhere near a race car but I like it a lot.

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Mike
"If I were you...... I´d rather be me." 😛
Check out my video:
http://www.7173mustangs.com/thread-my-mustang-in-action

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I got lucky and received the factory TV cable with the transmission... in fact, I got everything but the speedo cable and TV/Throttle Cable bracket (he still needed it for the throttle cable).

 

I'm thinking that by fabricating the new TV bracket so that there's no slack at idle, without changing the 'settings' on the TV cable, it should be pretty much where it needs to be (factory settings). If that doesn't work out, I'll probably just get one of those aftermarket valve bodies. And if it's too late and smokes the tranny, I'll think hard about just finding a 4R70W to go back in there.

 

Thanks for your thoughts on how it ran before you swapped out rear gears. It helps me to understand what I can look forward to, since I'd never actually driven mine before I tore it all apart.

Eric

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Hello Forum,

 

I'm running a 90 AOD in a 69 Torino with a 351W with mild upgrades. There are three things I have not heard mention in this post and having lived this pain I thought I'd share some AAR notes.

 

1). I didn't notice in this post any mention of the throttle / TV geometry corrector. I'm running the Lokar throttle cable and AOD cable. http://www.summitracing.com/parts/SOX-AS5-05K.

 

2). Homemade Lokar TV cable helper spring to pull the pressure back to near zero when there is no accelerator. This installs on the trans pan pulling the spring back to zero idle. The Lokar spring is pretty weak so it's fairly common to add a helper spring to pull it back when there is no acceleration.

 

3). Trans cooler. Going from an FMX to AOD requires some additional cooling (or so I'm told) so add a nice, high-end B&M trans cooler in front of your radiator. My radiator did not have trans cooler provisions in it.

 

A few other notes: 35 psi of pressure was too little on my trans but the most important thing (to me) was to ensure that I immediately got pressure when applying the accelerator. My TV pressure ended up being about 42 psi after tuning. Anything less and it sounds like my trans was grinding when downshifting from 2-1.

I added trans temp and pressure gauges in a discreet spot in my engine bay to ensure nothing zany was going on. Any time you adjust the idle you'll need to adjust your TV cable. 1/4 turn on the TV actually goes a long way. No need to burn up a trans. I'd add them in the interior but I don't have space.

 

-KR

-Former 70 & 72 Mustang Owner.

-69 Torino GT, Formal Roof, 351W, Edelbrock 600 cfm, Edelbrock 351W Performer RPM intake, headers, AOD trans, dual flowmasters w/H pipe, Pertronix II Billet, 3.5 TRACLOC g/r, 15" Magnum 500s, 100A alt, aluminum radiator, electric fan, Pro-car seats, mini-starter...owned since Dec 13.

-70 Mach 1, 351W, Edelbrock E-Street EFI, VHX instrument cluster, Hooker headers, dual flowmasters, Pertronix II, 15" Magnum 500s, 150A alt, aluminum radiator, dual electric fans, Pro-car seats, mini-starter

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In reference to your first two points, I'm using the factory TV cable set-up - so I can't answer for the Lokar users.

 

However, cars equipped with FMXs should have trans-coolers in the radiator, since the FMX required the same. I'm not saying that's the best trans-cooler solution available, but considering the FMX and AOD are very similar, it shouldn't be a problem for normal driving conditions (most AOD-equipped cars used radiator trans-coolers as well, after all).

 

"Good to know" information on the idle setting and the extra gauges. Thanks for sharing! ::thumb::

Eric

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Oh yes, roger that. The PO of my Torino routed around the radiator cooler and went with a cheap Haynes after-market cooler....probably because the radiator was shot as it was. I replaced the radiator and added the trans cooler lines back to it so mine routes:

 

Upper AOD (hot out) - inline tee temp - radiator trans in - radiator trans out - B&M trans cooler in - B&M trans cooler out - Lower AOD (cool in).

 

I don't put much stock in the radiator trans cooler and I tend to go with overkill when it comes to cooling and 45 yr old cars especially because I've lived in GA, NC, VA and I'll be moving to TX in about a year. Necessary? Maybe not, but it can't hurt and gives me a lil piece of mind.

 

In my opinion having the pressure gauge is an absolute must. My end pressure is actually 44 psi. It sits at zero in N with zero throttle and immediately creeps up when I give her some gas.

 

-KR

-Former 70 & 72 Mustang Owner.

-69 Torino GT, Formal Roof, 351W, Edelbrock 600 cfm, Edelbrock 351W Performer RPM intake, headers, AOD trans, dual flowmasters w/H pipe, Pertronix II Billet, 3.5 TRACLOC g/r, 15" Magnum 500s, 100A alt, aluminum radiator, electric fan, Pro-car seats, mini-starter...owned since Dec 13.

-70 Mach 1, 351W, Edelbrock E-Street EFI, VHX instrument cluster, Hooker headers, dual flowmasters, Pertronix II, 15" Magnum 500s, 150A alt, aluminum radiator, dual electric fans, Pro-car seats, mini-starter

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  • 1 year later...

What about steering column lock?

I haven't seen anyone address the extra rod that goes from the bottom of the shifter arm to the steering column that locks the wheel when shifter put in park.

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I rotated mine into the 'disengaged' position and zip-tied it in-place (so it doesn't inadvertently lock while the vehicle is in motion).

 

The key lock feature still works, so the illusion of security is still there. I can't honestly see the need to also have the transmission lock the steering column in-place for any reason.

Eric

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  • 1 year later...

I have the Cleveland engine with a FMX transmission. i want to do the AOD swap.  What year AOD will work with my Cleveland engine. I had an opportunity to buy a used AOD from a 1992 ford, but the both pattern would not work with my Cleveland engine.  The 1992 AOD was a one piece design. Did earlier models have  a two piece design?

 

Thanks Tom

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Nope. Mine is from 86 if I remember correctly and it's a one piece design too.

 

What engine do you have?

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302 (5.0), 351W (5.8), 351C (5.8) V8 engines, as well as the 3.8L and 4.2LV6 engines all share the small block bolt pattern. 1992 was a crossover year, where both small block and modular engines were available, and AOD and AOD-E transmissions were available. Small block and modular engines DO NOT have the same bolt patterns. There was also the A4LD non-electronic transmission available in 1992 and was used only on 4 cylinder and small V6 (such as 2.8 and 2.9) engines, and also does not have the small block bolt pattern.

 

The best AOD would be from a pickup. The ones used with a V6 were the lighter duty version, but can be rebuilt to heavy duty.

 

All AOD and AOD-E engines have one-piece cases and do not have a separate bellhousing.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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