C4 to 4r70w Swap Questions

[Ol'Blue]

Hey all,



Im starting to sort out my C4 to 4r70w swap and been reading a bunch of good threads here but have more questions and confirmations before I make my Christmas list.

• Using an AWD 4r70w out of a 1998 V8 Explorer. ID tag is F87P-7000-BA with black 7 pin connector. I have a mild build carbed 351 roller in front of it. I plan to take a risk and run it as is and hope for the best. Is this a totally bad idea? I havent pulled the pan to look for metal yet. Is there anything else I can check for health? Should I try and rebuild it myself?
• I’ve read that I should at least replace the torque converter. Should I stay stock or increase stall? There are a ton of options out there. What is a good fair priced manufacturer?
• With this trans I can run the WH adapter without taking the transmission apart? Will only have to shorten the output shaft.
• Buy Ford AODE/4R70W to Dana 20 Adapter (wildhorses4x4.com)
• US Shift controller and Throddle Position Sensor kit for quadrajet Quick 4 Stand-Alone Transmission Control with Remote Display (usshift.com)
• I plan to move the rear axle back 1” to compensate for the extra trans length but front may have to be lengthened.
• Modify stock cross member or buy aftermarket? Toms cross member looks nice but looks like it hangs low? Im leaning toward modifying the stock.
• I currently have Autometer trans temp gauge. Is there a port on the 4r or should I weld in a bung into the pan?
• Im currently running 4:30 gears and hear the overdrive may not like this tall gear.

Other details: D20, currently C4 J pattern with twin sticks, Duff long tube headers with their dual exhaust kit as well as long arms.



Thanks

 

[Master Chief]

You may have read these already but here are two tech articles regarding the swap that you are doing.

Roger

AODE & 4R70W 3 speed automatic - Transmission Guide

Tech article by Jon Hanna (Admin) Automatic Transmission Intro Gear Ratio Chart (see bottom of this page) C4 C6 AOD AODE & 4R70W 700R4 See also Manual Transmission Introduction Transmission: AODE & 4R70W (E = electronic, W = wide...

classicbroncos.com

4R70W 4 speed automatic with overdrive

Tech article by Tim Bowsher (Broncobowsher) Selecting a new transmission. It started with when I got the latest Bronco. I didn't want the old 3 speed anymore. I have heard about the NP435, so I got one. I ran along happily with 33's, 4.10's...

classicbroncos.com

 

[Broncobowsher]

• If inside the pan looks good, I don't see any reason to rebuild it. If you want to play a little bit, get RK-AODE-2 for 96-2000 4R70W from Baumann (the same source as the stand alone controller) There shift kit is really cool in that each part is labeled for what it does. One of the bits is a little more line pressure to handle engine with a little more torque.
• If the pan looks that good, I would reuse the convertor. But if you want to replace it, stock is what you want. It has good creep force at idle but under load it already has a fairly high stall (compared to the old 3-speed factory stuff). Expect about 2000 RPM
• Looks like you have a 4WD transmission with the large 6-bolt pattern and the 31 spline output. With the correct adaptor, yes. You didn't specify which adaptor, there are at least 2 different ways of doing it. One of them is what you describe, the other is rebuild to install. The adaptors are made by https://www.advanceadapters.com/ and retailed by Wildhorses
• Oops, you did specify. Yes that is the right one.
• Yes, good stuff.
• Not going to say this will be enough. Measure when you are done. I bet you still need the rear shortened and the front lengthened.
• Either, or build your own from scratch. I never used that adapter (I used the rebuild the transmission version) so I can't comment on what it will take to make the Explorer transmission mount work. Also clearance for the front shaft to the pan may require a new smaller diameter shaft.
• Bung in the pan.
• 4.30 gear would probably be acceptable for 33" tires. You are a lot closer than those starting with 3.50 gears. Tire size, how happy the engine is making torque under 2000 RPM, drag, lift, where you live and how you drive will tell how well the 4.30 gear will work. I will say they are close enough to at least run them as is before planning on changing anything. They may be close enough.

 

[Ol'Blue]

Thanks for the help gents. Remove the pan today and there is about 2” diameter of material around the magnet. Is this considered excessive or a reason to rebuild?

 

[Wrightracing]

Definitely time to rebuild. Make sure to flush the cooler and lines. There is probably stuff in the cooling system. After I did my Transmission, the builder put a inline magnetic filter and removed it after 2000 miles.

I am building 72 project Bronco and I will be running a 408w or 427w and I am torn between the AOD and C6. I already have both of them. I will use it as a desert toy, not a daily driver. I will probably go with a manual valve body. I like running in the sand dunes and heat is always a issue. I also run long trips in Baja, so the AOD overdrive would be nice for that on highway 1.

Good luck.

David

 

[stretch]

Performed the same swap that your looking into. 98 Explorer awd. Installed without a rebuild, and lost all forward gears within 100 miles.

I rebuilt the tranny myself using the Transmission Shop kit and video series. The Gent that teaches the series reminds me of Mr Rogers but that is a good thing. you May want to look into it. 1k miles in the rebuild and going strong.

One other item you may want to look into is the long tube headers. There may be a figment problem there. Seem to recall posts regarding this problem.

 

[badandy73]

Did this same swap earlier this year using a '98 trans as well, one of the best upgrades I've done paired with a 347. Couple of thoughts based on your list:

Shop rebuilt my donor and supplied an OEM style 'high stall' torque convertor, which is working great instead of paying $$ for aftermarket.

Had the same concern with the Tom's cross member kit, but it bolted right in and doesn't hang much lower than the stocker.

4R has a built-in temp sensor and if you're running the quick 4 it displays temp on the home screen in real time. So, no need to butcher up the pan unless you really want a redundant reading.

Agree with what's been said about the drivelines; shortening/ lengthening drivelines is a lot easier than moving the rear end back- I ended up buying new HD units F/R from Tom's.

Good luck, cheers!

 

[Ol'Blue]

Thanks for the help! Been calling around for a rebuild and estimates are $1,500 - $2,500 which includes the converter. Wow!

I may try and rebuild it myself. @stretch I couldn't find the Transmission Shop kit and video on line. Do you have a link?

Also are there other good brands for rebuild kits other than the Transmission Shop?

 

[Ol'Blue]

@stretch I think I found the series. The Transmission Bench and yes very Mr. Rogers. Is this it?

 

[Wrightracing]

$1500 to $2500 is not bad. I assume that is not a performance model, but just a OEM rebuild.

I paid $5500 for my 4r100 with a performance shift kit and a upgraded converter.

Last time I had my AOD rebuilt with a shift kit it was close to $3000.

You get what you pay for.

David