31" tires with 4.56 gears, what trans?

[LoneRanger]

I'm reverse engineering this project for next years SuperCel.

Okay I may have found a truck for Panda- 74' six cyl 3 on tree, factory 4.56 gears!

Is there an auto trans that will let this thing cruise at 65mph with a 31" tire without turning 3500rpms?

Discuss!

L.R. ;D

EDIT: we are NOT keeping the 6cyl- it's getting swapped for a 302!

 

[okie4570]

I'm curious here too. I've got a 66' with 3 on the tree, a 200 6cyl and 4.56. It's only got 225/75/15 on it now and it is completely wound up/screaming at at 50mph lol.

 

[Broncobowsher]

You want auto, with overdrive. That is a fairly small window.
I can't think of anything that will bolt to THAT engine, bellhousing.
If you did a V8 swap...
or a later I6 that uses the V8 bellhousing bolt pattern. That would let you slip in a 4R70W without much issue.

No matter what you will be pushing for a short rear driveshaft. Since the tire size is small enough I bet it isn't lifted. Which will help. That rear driveshaft will be about 6" shorter (3" due to running a V8 length transmission over an I6 + 3" since the overdrive is about 3" longer than a V8 length transmission). Don't plan on a lift.

 

[SavageBurro]

The 4r70w auto has a .7 overdrive. With 31" tires and 4.56 gears you'd run about 2250 rpm at 65 mph.

http://www.4lo.com/calc/gearratio.php

 

[Justafordguy]

Not sure how you would adapt a 4r70w to a 200 I6 ?

 

[LoneRanger]

Original post is edited. We are running a 302. Lift will be 2-2.5" street truck.

L.R.

 

[Justafordguy]

Oh, that's a different story then. Yes a 4r70w is a great option.

 

[Apogee]

You could build an AOD with beefed internals if you wanted to avoid the electronic shift controller need with the 4r70w, otherwise I'd go 4r70w myself for the added level of control. The AOD is a .67:1 OD ratio IIRC (~2300 RPM @ 70 MPH), versus .70:1 for the 4r70w (~2400 RPM @ 70 MPH) with 31" tires and 4.56 gears.

 

[sykanr0ng]

If you are using Explorer based EFI then the 4R70W.

If you are not using Explorer based EFI then the AOD (possibly rebuilt with 4R70W internal parts) makes more sense.

The PCM for the EFI also controls the 4R70W.

 

[904Bronco]

The 4r70w auto has a .7 overdrive. With 31" tires and 4.56 gears you'd run about 2250 rpm at 65 mph.

http://www.4lo.com/calc/gearratio.php

I can confirm this RPM number is close, as that is what I have in my 68. About 2300 is what it is.

 

[LoneRanger]

Sounds to me like AOD is why I am looking for then. No electronics, can be built to handle hp and torque, and it can bolt on!

2k sound reasonable for a new built trans shipped to me?

 

[G's Baja Bronco]

AOD from full size bronco (this will have the right 4x4 output shaft and adapter) NP205 bolts right up.
1985-'90 Bronco with 5.0 V-8 engines
G

 

[Broncobowsher]

Sounds to me like AOD is why I am looking for then. No electronics, can be built to handle hp and torque, and it can bolt on!

2k sound reasonable for a new built trans shipped to me?

4R70W can get you a better transmission for less money when all said and done. Stand alone controller is capable of working with EFI or carb applications. The selectable lockup convertor gives half gear steps that makes it so much more drivable.

 

[LoneRanger]

Will be running fitech efi/ explain the stand alone controller. I prefer simple over complex.

 

[Galt72]

http://becontrols.com/aode.shtml

 

[LoneRanger]

575 for the basic trans controller plus the cost of a trans, that's no deal to me. Recommendations on a shop to buy the correct well built AOD trans?

L.R.

 

[needabronco]

If your plan to use the D20 you need the adapter and output shaft before you rebuild your transmission. That's going to be around $600 regardless of what transmission you use. The AOD gets dogged on quite a bit here, but it is still a good viable transmission. Keep an eye out in the classifieds for one that already has the adapter bolted to it. They turn up a few times a year.

Does this Bronco have the D30?

 

[Broncobowsher]

575 for the basic trans controller plus the cost of a trans, that's no deal to me. Recommendations on a shop to buy the correct well built AOD trans?

L.R.

$425 for the controller.
$150 if you can't splice wires and buy the harness from them as well.

 

[LoneRanger]

^ yes, that's how I came up with the 575 number. New build, new parts. I dislike wiring, if you would be interested i'd be glad to have you stay with us for a while if your willing to lend a hand. Disney world is an hour and 20 minutes away.

L.R.