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AOD Rebuild + Driveshaft Q

FoMoCoBronCo

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Feb 20, 2023
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99b879ba61d83aef806138802c341a2a.jpg



In the tech article on transmission swap options, the AOD stands out to me as the best fit for me (mechanical, not electrical, cheaper than newer, electronically controlled options, and has OD)

I have two questions:

1. The author states that durability is a con, but that some transmission shops specialize in “beefing them up.” If I was interested in buying one already rebuilt, can anyone recommend a company that sells rebuilt AODs that have been beefed up? I’m in Atlanta, but can have something shipped. I saw that Monster Transmissions online has quite a bit of inventory and has what they call a “heavy duty” rebuild available for AODs.

2. The author also talks about clearance issues with the driveshaft. I’m planning on simultaneously installing a 1” body lift with the transmission install. i don’t have a suspension lift currently, but if I do install one in the future, it would be 1.5” max for a total of 2.5”. Could someone who has done this before elaborate on what I can expect from clearance issues within an AOD swap and a 1 inch body lift?


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FoMoCoBronCo

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Feb 20, 2023
Messages
72
I have a 71 with the original 302 bored 30 over, stock heads, edelbrock manifold and carb. I currently have a C4 installed.


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Broncobowsher

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Jun 4, 2002
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You also need the correct axle gearing paired to the tire size. If you have the stock 3.50 gearing, it won't be happy/survive. Stock 4.11 gearing, might work fine if you are keeping the stock tire size. But it sounds like a lift is coming and that will mean larger than stock tires.

Getting the TV adjustment correct is a must. Not just there and hooked up with a range of travel. But the correct travel settings during the throttle sweep. It's easy to get it to work, hard to get it to work right.

Having driven both an AOD for many years, and a 4R70W. There is no way I would ever suggest getting an AOD. To make one better isn't hard considering the low bar that it starts at. Marginally OK is an improvement over it sucks. If you are a die hard no electronics guy but still have to have an overdrive automatic, 700R4.

As for driveshaft, measure after installing. Don't try to order ahead of time. Broncos are really good about not being the same in the driveshaft department. Which adaptor was used, what is the pinion angle set to? Because angles don't work that way, moving the transfer case back 1.5" does not mean you need a 1.5" shorter driveshaft. You moved a point, changed angles, not straight line math.

AODs before 1988 had oiling issues. Well known. Get an older one and the gears will be trash, even if it came out of a driver.
You can get a good newer electronic transmission that has all the upgrades in it and the controller for less money then getting an AOD and paying someone to put good parts in it and will probably screw it up anyway.
 
Last edited:

Apogee

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Nov 26, 2005
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I'd also note that a 4R70W is essentially a beefed up AOD/E transmission, even in it's weakest original form, so what you spend on beefing up an AOD, you might just be better off spending on a 4R70W swap and then enjoying the additional benefits of electronic control.

Otherwise, there are definitely a few AOD guys here that can share their personal AOD adventures, good and bad.
 

bronco italiano

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I have a custom built AOD and quite frankly really like it.
I do not have a big motor though, mid-performance rollerblock 302 that only puts out 285 ft/pd torque.
My transmission guy used the Transgo kit, had the drum machined for an extra clutch, but I don't have lock-up capability.
Works well, yes I would like to have more control of my shift points and be able to lock up.
I did contact Silverfox, he is well known n the Mustang arena. He was gonna build me an AOD but manual valve body and it ain't cheap.
No way with 3.50 gears. I had to go 4.11 and that barely makes it on the highway without lugging the engine at 70 mph with 31" tires
At the end of the day, I allowed the cheap Portuguee in me to save 1,000$, only to spend another 3k for a 4r70w with lock-up converter/US shift/etc.
 

Broncobowsher

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Be careful with the non-lock up convertors. In overdrive the RPM is easily low enough that the convertor will slip. This turns fuel into heat inside the transmission.
 

ba123

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Oct 29, 2022
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I don't have enough on my AOD yet but you can at least hear the first three gears on my last post on my build thread linked. I like it so far and I think a lot of the negativity about it is not difficult to overcome, although don't know how hard the upgraded parts are to come by now. I have the wide ration gearset in mine as well as a non-lockup custom converter and a hardened input shaft. All my internals are higher end. I just got a valve body that allows me to shift 1-2-3/Dr and engage OD with a button (Bronco Italiano has this as well), vs doing the 1-Dr-1 shuffle like I did in the video.

And yes, like Bowsher mentions, the temps will be much hotter with a non-lockup but if you use good fluid, that really shouldn't be a concern, the way I understand it.

BUT...

Not sure you're going to find all that stuff I mentioned and stay at a reasonable price vs doing one of the newer ones mentioned. Looks like the one from Monster is about $3500 and then another $500 if you don't have a core. Guarantee looks great though.
 

bronco italiano

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Monster I have heard lots of horror stories regarding the return procedure/quality.
Do your homework carefully.
 

Broncobowsher

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You can still get a good take out 4R70W and not even pull the pan and run it. Comes with most every part used in an AOD upgrade already installed, plug stuff you can't get in an AOD (like a selectable lockup convertor, not one that is just 100% locked in OD no matter what or custom where there is no lockup at all) The money saved on doing a rebuild and upgrades will pay for the controller and still leave a wad of cash in your pocket.
 

399strokerEB

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I'm running an aod in mine, stock form lived behind my high compression 351 stroker for years on 37" boggers. Still running it today behind my stock 351 I swapped in. Next plan is to install the 4r70 first and second gear.
 
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