How to replace ZF with AOD

[Mr. Dawg]

Hello,

I'm in need of your guidance please...

I have a beautiful restored uncut 77 that is setup with a built up 5.0 HO w/ Sniper EFI, ZF 5 speed and twin sticked Dana 20. I'm running stock 3.55 gears with 31x10.50 tires. This is primarily a show truck.

I 'm considering replacing the ZF with an AOD to make it more pleasant for me and make it much easier for my family members to drive.

Besides obtaining a quality rebuilt AOD, what other parts and what all do I need to do to perform this swap?

Would I be better off going with an 4r70w instead of the AOD?

Thank you for your thoughts and advice.

 

[bronco italiano]

Taking a primarily show truck off road may be a bad idea?
AOD conversion is flex-plate/SBF bellhousing/AA transfer-case adapter (That must be done when the trans is built/US shift (electronic AOD)/Crossmember

Not sure if regular AOD and Holley sniper will work on the TV cable.

I would leave it alone and enjoy it.

 

[jamesroney]

Taking a primarily show truck off road may be a bad idea?
AOD conversion is flex-plate/SBF bellhousing/AA transfer-case adapter (That must be done when the trans is built/US shift (electronic AOD)/Crossmember

Not sure if regular AOD and Holley sniper will work on the TV cable.

I would leave it alone and enjoy it.

Gotta find some way to keep that automatic transmission cool. If it's running a ZF, then it already has a 31 spline converted Dana 20, and that will bolt to a 4x4 AOD. Clocking might need to change for driveshaft clearance. Everything else that @bronco italiano said is correct.

Plenty of guys looking for a good small block ZF. Should be able to get some of your investment back.

 

[dmoses42]

Your question on AOD vs 4R70W.... AOD is not electronically controlled, but the 4R70W is, meaning if you go 4R70W you will also have to get a transmission controller. I don't think there is much of a difference gearing-wise between the AOD and 4R70W. I've not done either swap, I'm just going from the reading on the subject on this forum. Someone will chime in if I'm wrong, I'm by no means the most knowledgeable on here.

 

[Broncobowsher]

The 4R70W has lower gears than the AOD. With the 3.50 gears, the lower transmission gears would be much better.
If you get the 4WD version of the 4R70W from a 5.0 Explorer or a 4.2L V6 F150 it will take the place of the ZF. Not positive, but a good chance of the length to a match between the two. Yes, need a controller. But worth it.

You will need rubust transmission cooling. Correct balance flexplate for your engine.

 

[dmoses42]

The 4R70W has lower gears than the AOD.

Thanks for clarifying, I didn't think there was much of a change gear-wise, but I didn't check either so that's my bad...

 

[rocknhorse76]

4R70W has a better gear ratio spread. Lower first gear and OD ratios. A 40,000 GVW Long (brand name) transmission cooler fits nicely in front of the radiator and will keep the 4R cool and happy. The stock exploder torque converter is great too. It has a stall of 1900-2200 rpm with a 5.0.

 

[Mr. Dawg]

Thank you all for your replies and feedback. Much appreciated.

I need to learn more about the 4r70w swap.

Thanks!

 

[ba123]

You can go AOD and get the wide ratio gear kit which puts the better gears in the AOD and isn't electronically controlled. That's what I did.

I can't say either is better, it's just about what you want.
My modified AOD gears are: 2.84/1.55/1.0/0.67
4R70W gears are: 2.84/1.55/1.0/.70

You need to rebuild the trans anyway when you put the adapter in, as it's the first piece to go in at the tail when built.

Although cost wise it might be less for the 4R70W, not sure.

 

[Broncobowsher]

Since you are starting with a ZF, you have the ZF adaptor. That adaptor will bolt to the back of a 4WD 4R70W WITHOUT having to do a rebuild and replacing the output shaft. If you start with a good transmission, no rebuild needed. Just bolts on (maybe a trim of the output shaft, that can be done without removing with a cut off wheel). The key is starting with a 4WD version of the transmission. If you start with a 2WD version, rebuild will be required.

 

[Madgyver]

Get the 4R70W gears installed into the AOD and get a built valvebody to solenoid lock out OD. You then won't need a transmission controller.

 

[ba123]

Get the 4R70W gears installed into the AOD and get a built valvebody to solenoid lock out OD. You then won't need a transmission controller.

Mad, do you have an ape set up that way? I did some mods using a valve body kit forever ago and don’t remember what I did do fully prepared once I finally get to drive it that if I’m not happy with the shifting, was gonna do this and like what I saw at Silver Fox. If you have this, which co did you go with?

 

[Broncobowsher]

By the time you invest in the gears, valve body, custom build...
You spent way more than just buying the controller and a good used 4R70W. And you still don't have the level of control that the controller gives over the AOD. You can keep throwing more nd more money at the AOD to get it closer to what a stock 4R70W is but you will never get there.

 

[ba123]

I agree. I bought my AOD when that was the best thing out, sadly... even more sad that I still haven't gotten to try it.

If I had to do it again, even looking at my receipts from 20+ years ago, I wouldn't do it again unless I already had the trans and a cheap source for parts.

 

[nvrstuk]

I have done this exact ZF to 4r swap 13 yrs back. Wish I could remember all the small details but everything rocknhorse & Bowsher has said about the advantages of the 4r over the AOD is important to remember.
Find a used, fairly low mile 5.0, 4x4, 4r70 trans from the correct year range (starts Aug '97 I believe), and go from there. They are still out there! The lower gears in the 4r with a stockish 5.0, and stock 3.5gears is a very important detail that most miss. The OD in the 4r is very usable. The USSHift controller gives you 2 or 4 tunes (2 is plenty) so you can have one dialed in with soft smooth shifts for other members of the fam and then you can have a more aggressive trans tune for when you want a more "crisp" ride out of your EB.

Search the tech articles here, somebody has to have written a tech article on all the details and procedures of the installation of the 4r in an EB.

Good luck, you won't go wrong with the 4r. It is a HUGE step up in comfort and convenience over a ZF for around town-besides the fact that you can now enjoy cruising along with your double scoop ice cream wandering the back roads if you have the 4r- but not with the ZF! Enjoy it.

 

[76Broncofromhell]

No one has suggested a 6R80 yet? Unless you can find a 5.0 Explorer to pillage completely you are going to be in it nearly the same amount.

Same length as a 4R70W, light years stronger. Used transmissions are much more robust and easier to find with far less miles on them with any 4R.

I would not run an AOD in anything. Especially given their history of lackluster survivability. They are also pretty hard to tune the shift points without pretty extensive valve body work.

 

[nvrstuk]

I am probably the biggest proponent of 6r80s in a Bronco, anywhere LOL

The cost of a total 6r80 install is much higher than a 4R70. I've done both of them several times and I currently make adapters for small block fords to bolt up to a 6r80. So far almost all the ones I've sold are for EB use.
6r in a 5.0 with 4x4 are very hard to find. Price has tripled in 4 yrs for a good used one-not exaggerating.

There are many advantages to a 6r but the cost is higher.

I wrote a very detailed article for Bronco Driver Magazine on installing 6r80s in EB's with fifty pictures and about ten pages of instructions. I also have that same write up posted here and I will link it below

 

[nvrstuk]

Here ya go.

https://classicbroncos.com/forums/a...-trans-into-a-bronco-behind-any-sbf-engine.2/


I am working on a simpler tc adapter.l for the 6r.
Important life things are in the way so it is a back shelf project.

 

[Madgyver]

By the time you invest in the gears, valve body, custom build...
You spent way more than just buying the controller and a good used 4R70W. And you still don't have the level of control that the controller gives over the AOD. You can keep throwing more nd more money at the AOD to get it closer to what a stock 4R70W is but you will never get there.

I had all the hard parts available other than the valvebody.

 

[Madgyver]

Mad, do you have an ape set up that way? I did some mods using a valve body kit forever ago and don’t remember what I did do fully prepared once I finally get to drive it that if I’m not happy with the shifting, was gonna do this and like what I saw at Silver Fox. If you have this, which co did you go with?

https://lentechautomatics.com/products/