Drivetrain combo and AOD Swap?

[NickC24]

Hi guys newbie here.

I'm have been doing research on drive train combos and I think I have settled on a 302 with an AOD Trans. Looking for a daily driver that can go on the freeway. Not much of a 4x4 vehicle.

My question is on the AOD. I found one on CL from a 92 thunderbird (which I've heard is a good year and model). Since that vehicle isn't 4x4 can I use it on the Bronco? Also since its newer does that mean it's electric in some way. Is there a conversion that will need to be installed.

Thanks for the input and if you guys know of a better combo for what I'm looking for please let me know!

 

[Broncobowsher]

I'm pretty sure that the '92 T-bird is still the all mechanical AOD and not the better electronic AOD-E.

In all honesty, it is a bigger can of worms than you are thinking it will be. In order to keep the transfer case it needs a conversion kit. That conversion kit includes a new output shaft. And the output shaft is installed through the front of the transmission. In order to do that the whole transmission has to come apart. That is even if the transmission is working perfect right now, it needs a full rebuild to make it usable in a Bronco.

Next the gearing. What size tires are you running (or planning on running)? What axle gearing do you have? You are probably going to have to regear the axles in order to make that transmission work for you. The AOD has a very tall overdrive. 2/3s, .667 is the ratio. Most Broncos were built with the standard 3.50 gearing. That comes out to an effective ratio of 2.33:1. A 302 does not produce enough torque to push a Bronco down the road with that little gearing. It will hunt in and out of overdrive continuously at highway speeds. Continuous shifting will kill the clutches in the transmission.

Guessing tire size (let us know what you are going to be running) in the 29-33" range based on the daily driver comment I would guess you are probably going to need axle gearing in the 4.56 range in order for that transmission to work.

A popular option is the 4R70W, typically from a '69 to '01 5.0 V8 Explorer. Get one that is from a 4WD/AWD model. You can use the ZF adaptor to make the Dana 20 transfer case mate to the transmission. No need for a rebuild to change output shafts going this way. Add in a stand alone transmission controller. Now you have a modern transmission with a selectable lockup convertor (can act like another gear ratio splitting transmission ratios). Has all the updated parts that costs a good chunk of money to put into an AOD. Some AOD rebuilds include the purchase of a 4R70W just to rob it of the upgraded parts. The OD is till pretty steep, but not as steep at .70:1. Still waiting on your current gear ratio and tire size, but will still generally require regearing to make it work. (If you have the optional 4.11 gears and are running the stock ~29" tire you may be able to get away without regearing)

 

[needabronco]

92 is still an AOD, as said it will need a rebuild in order to install the output shaft, frankly I'd consider any used anything a core that needs rebuilt unless the mileage and maintenance can be verified. AOD's are more complex to rebuild than say a standard C4, but they are doable if your mechanically inclined, otherwise your paying a transmission shop for a rebuild plus around $550 for the adapter kit.

As Bowsher said you'll also be in for a set of gears for your axles as you will absolutely need deeper gears in order to utilize OD, but that will be a given for any transmission with an overdrive.

I've been running an AOD for about 6 years and overall I'm happy with the transmission. I would have installed deeper gears than I had, I have 4.88's and 35"s and should have gone to 5.13's or 5.38's

 

[NickC24]

I'm pretty sure that the '92 T-bird is still the all mechanical AOD and not the better electronic AOD-E.

In all honesty, it is a bigger can of worms than you are thinking it will be. In order to keep the transfer case it needs a conversion kit. That conversion kit includes a new output shaft. And the output shaft is installed through the front of the transmission. In order to do that the whole transmission has to come apart. That is even if the transmission is working perfect right now, it needs a full rebuild to make it usable in a Bronco.

Next the gearing. What size tires are you running (or planning on running)? What axle gearing do you have? You are probably going to have to regear the axles in order to make that transmission work for you. The AOD has a very tall overdrive. 2/3s, .667 is the ratio. Most Broncos were built with the standard 3.50 gearing. That comes out to an effective ratio of 2.33:1. A 302 does not produce enough torque to push a Bronco down the road with that little gearing. It will hunt in and out of overdrive continuously at highway speeds. Continuous shifting will kill the clutches in the transmission.

Guessing tire size (let us know what you are going to be running) in the 29-33" range based on the daily driver comment I would guess you are probably going to need axle gearing in the 4.56 range in order for that transmission to work.

A popular option is the 4R70W, typically from a '69 to '01 5.0 V8 Explorer. Get one that is from a 4WD/AWD model. You can use the ZF adaptor to make the Dana 20 transfer case mate to the transmission. No need for a rebuild to change output shafts going this way. Add in a stand alone transmission controller. Now you have a modern transmission with a selectable lockup convertor (can act like another gear ratio splitting transmission ratios). Has all the updated parts that costs a good chunk of money to put into an AOD. Some AOD rebuilds include the purchase of a 4R70W just to rob it of the upgraded parts. The OD is till pretty steep, but not as steep at .70:1. Still waiting on your current gear ratio and tire size, but will still generally require regearing to make it work. (If you have the optional 4.11 gears and are running the stock ~29" tire you may be able to get away without regearing)

Thanks for the input. I will be running 33's at the largest with probably a 2.5" sus lift and 2" body lift to make everything fit a little easier. I like more of a stock look. I have decided to go with a full injected 351 that I got of CL, in the process of the rebuild. I will go with your suggestion on the trans and may have found a 4R70W but it is out of a 2003 5.4L F150 4x4. Will the new controller work with a trans that is that new. Also what controller would you recommend. Also does it matter that the its a 5.4 and not a 5.0 like the 351. What gears would you recommend for that combo.

Thanks again for the feedback. Super helpful.

 

[Broncobowsher]

The 5.4 is a modular motor, different bolt pattern than a small block V8. That transmission won't work for you.

 

[NickC24]

The 5.4 is a modular motor, different bolt pattern than a small block V8. That transmission won't work for you.

What about a 4.6. I am having hard time finding a V8 5.0 and have seen on other forums that the V6 should work. Not sure so I though I would check here.

 

[Broncobowsher]

4.6 is still the modular overhead cam engine. They are different.
The 4.2 V6 uses the old school 5.0/302 bellhousing. Just can't use the flexplate as the balance is different.

The modular V8 engines are easy to find. That has been the prime V8 engine for the past 25 years. The last car to get the classic 5.0 was '95 and it only lived on in the trucks for another year or two with the exception being the 5.0 Explorer that lasted until '01. So the newer the stuff, the less it was used, and that will make finding them a little more difficult.

 

[needabronco]

If you do go with a V6 transmission you will need to add clutches in order to match the V8 transmission's spec's, if I remember correctly there's a solenoid or two that are different as well, but don't quote me on that.

 

[EFI Guy]

The 98-01 5.0 Explorer is the best donor for the trans. It got some internal upgrades that the 97 and earlier didn't have.

You can also use the Explorer computer to control the trans if you're adding EFI to the 351 at the same time. It's a little more work and $$ to adapt to a 351, but the stand alone controllers aren't cheap either. You can find more info in the link in my sigline.

 

[jdbronco]

I don't want this to come off sounding rude, but by the sounds of it I think you need to do a bit more research before you start buying parts. Get a good handle on the history of Ford motors and transmissions so that you know what vehicles you can get your parts from. Ford had more nuances to bolts patterns and such than GM did. Not everything is interchangeable.
AOD needs to come from a 302 V8 vehicle, preferably 88-93 although for the most part they stopped using them in '91. You will need to change the output shaft so 2WD vs 4WD trans doesn't matter. Many people go with the newer 4R70W but that requires either fuel injection or a standalone controller since the transmission is electronic. Also needs to come from a 302 V8 vehicle to make life the easiest.
There is a lot to learn about the engines as well, things changed over the years and I learn more everyday. I'm not trying to be rude, I am just trying to help you before you throw down money on parts that won't end up fitting.