How to: - C4/D20 Swap in Progress | Ford Explorer Forums - Serious Explorations

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How to: C4/D20 Swap in Progress

Prefix for threads which are instructional.
well, I started my tranny/t-case swap last sunday. its a Ford C4 auto 3-speed out of a 70s model Bronco that I rebuilt myself. I also installed a B&M Transpak Shift kit. The transfer case is a D20 out of the same Bronco and it has Twin Sticks. my buddy TJ came by the house with his tow rig and trailer and we trailer the Sploder to his place. while he went out to eat I stayed behind and started workin on her....

here's a quick breakdown of the progress so far....

Sunday::
Removed both front seats, pulled back the carpet to the back seats, unbolted the factory plate covering where the manual shifter would come up if I had a manual tranny. I then unbolted the d-shafts from both ends and drained the tranny. Also, the transfer case was dropped.
(removed broken pic links)

Monday::
TJ and I unbolted the tranny and started pullin it.... I"m glad I'm puttin in an older tranny, none of that crappy electical connection crap!! and yes, that's all we got done monday, it was a PITA pullin the tranny without droppin down the exhaust.

I will be back out there on Thursday, so I will post updates by just editing this post.... Lemme know what you think so far.

==Ryan
 



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so drop the exahust y pipe, it makes it so much easier!

Nice work thus far.

Did you do anything to the D20?
 






what kind of adapter did you have to get to bolt it on to your motor? Also why not use a newer C5 or C6?
 






C5 is an early version of the C4 used in some early Rangers and BII's.
The c4 only needs a 2.8L V6 bellhousing, new flywheel and starter (torque converter) to bolt to the OHV 4.0L, making it similar bolt pattern to a C5.
A C5 will explode behind a 4.0L, unless it is rebuilt with C4 parts.

A c6 tranny uses a 163 tooth flywheel found on 90 degree v8 engines.

you have three choices for an automatic with a OHV 4.0L:
A4LD, C4 or convert to 700R4
 






everything that 410 said.....

and the only thing that's been done to the D20 is the Twin Sticks.... I don't have the money for the 4:1 right now, b/c after this is done, I"m gonna be startin my FWD44/9" swap. Thanks for the compliments.

--Ryan
 






Nice work so far, keep us updated :)
 






Very nice, i really really want to do this to my truck.

Is the D20 a stout tcase in stock form? Is it lower then 1354?

How hard is the C4 to rebuild? I want to go to a local yard and pick up this combo, but i've never had a tranny apart, although i'm pretty handy in the garage.
 






Nice work Ryan, I'll be looking forward to seeing Slider all done :)
 






from what I understand the C4 is simple to rebuild in your garage.
The D20 is a stout case, gearsets are available for it and it is similar in size to the stock cases.

The only problem witht he D20 is they are old, and they can break when used in the heavy truck with a powerful engine, big tires, etc,. The good news is they too are cheap and easy to rebuild (relitively speaking)
I say run it till it pukes, then start over :)
This is going to be a nice combo, you might miss that OD though......
 






OD would be nice to have, but i drive my explorer once week, just enough to keep the battery charged, lol.

How much did this combo cost you to pick up CarFreak??

I'm assuming you'll have to make a custom cross memeber too, that's no big deal.
 






JoshC said:
Very nice, i really really want to do this to my truck.

Is the D20 a stout tcase in stock form? Is it lower then 1354?

How hard is the C4 to rebuild? I want to go to a local yard and pick up this combo, but i've never had a tranny apart, although i'm pretty handy in the garage.

thanks, yes, the d20 is a very stout case (gear driven vs. out chain driven fac. ones).... the C4 was REALLY easy to rebuild.... wow, it was easy, you just gotta pay attention to what youre doin... this was my first one, and I had no problems.... now, I haven't tested it yet. hahaha.....yes, its low range (from what I'm told) is 2.96:1

also, I picked up the combo already bolted together and already twin sticked for $150, that's an uncommon price though, usually they're more expensive than that.

yes, I will need a new xmember, cooling lines, and d-shaft mods... but that's no biggy, that stuff my buddy can do. (as I'm still learnin to weld and don't trust myself yet)

Just got back from being out there tonight.... I didn't get much done, b/c the torque converter probably won't be in until monday, so I'm just workin on the details now.... I removed the factory console brackets, and the rear seat A/C vents. I also replaced the carpet and the drivers seat so I could decide where I want the shifter.... this is a HARD decision.... b/c I don't have the tranny up yet, so I don't know where the twin sticks will be comin up at, and I don't know how high I want the shifter mounted...... oh yeah, I also removed all the wiring from my old stereo system.

--Ryan (sorry, no pics tonight)
 






So you say it came out of a 70's Bronco, what does it look like, just so i know i was getting the right tranny combo?

Also, can you get a measurement for me. Can you mean it from the front of the bellhousing to the very end of the yoke on the transfercase when they are bolted up? Thanks.
 






I measured it the other day, and if I remember right, from the bellhousing to the yoke on the output of the t-case, it was 34" long. the c4/d20 combo is about 4" shorter than the A4ld/bw13-54 combo. and yes, it came out of a 1970 bronco..... now, I have been told that you need a case fill C4 to bolt up to the C5 bellhousing, (the case fill are the later model c4's) but I put the bellhousing up to the c4 and from what I saw, it will bolt to my pan fill c4 with no problem. I can get a better picture this weekend when I'm out there workin on it.. (I keep forgetting my camera to take pictures.)
 






UPDATE::

Tonight, I got what I thought was a lot done. I unbolted the A4LD flexplate and spacer off the rear of the engine, Cleaned up the space, then replaced it behind the new C5 Flexplate. I then finished installin the shift kit into the C4 valve body. It was when I was puttin the pan back on that I realized that the inlet where the pan goes into that pan at was serperate, meaning there's now a hole in the side of my pan, so I've gotta hunt down a "new" one now.
I also pulled the carpet back again to gain access (once again) to the hole in the floor for when the tranny gets bolted up, the twin sticks will have a place to stick through at. oh yea, I also made a REAL dumb move and knocked over a pan of old trann fluid.... yeah, like 6 quarts of fluid EVERYWHERE!!! That's all for tonight..... I have decided that I will just post all my pics once the swap is done.... and hae one big long post of just pictures from start to finish.

--Ryan
 






Keep us posted :) ATF is a PITA to clean up, I know.
This is the 7th trans I have put in my 88 :)
 






ok, sorry I haven't posted in a while, been busy on the truck.....
The C4 is now bolted up and ready to go (minus shifter cable, Type F fluid, and cooling lines)..... I test fitted the D20 last night ot see where my twin sticks are gonna come up at, and oh MAN does it hang down low!! I"m hopin that I can inexpensively index it up a little bit...... I have the newest pictures up on my CarDomain Page on page 9..... I would host them, but the site isn't wantin me to do that right now for some reason.

oh, last night, we loaded up the truck to take it to the fabricator to have the x-member fabbed up and the d-shafts modded, and dependin on how much he'll charge me, I may have him mock up a t-case skid too.... only thing that kinda dissappointed me was that he won't be able to start on it until Monday :( oh well, I was planning on having it for this weekend, but I've waited about 3 weeks to drive it, what's another coupla days.... let me know if you have any ideas on clockin the t-case, and what you think of the progress.

--Ryan
 






Well, Saturday, I went back out to the Fabricators to talk to him about what I want/need him to do.... he's gonna use my existing tranny crossmember and just modify it to work with my tranny, he's also gonna bend my twin sticks a little bit so I have better clearance. I have decided that I'm gonna use my factory t-case skid too, b/c I shouldn't have to modify it any. oh, and one more thing, while he's workin on it, he's also gonna weld up the rear for me :D

--Ryan
 






thinking about going c4 myself one day. Do you happen to have the casting # off the bellhousing so I can be sure I get the right one when I do.

:chug: :chug:
 






no, I don't but to help you out.... just get a c5 bellhousing from any mid 80s ( i think mine's from an 85) with the 2.8 V6 and the C5 tranny, you will also need the C5 Torque converter and the C5 flexplate. oh, and also, when you get your c4, make sure the one you get is a CASE FILL transmission, not a PAN FILL.... I got my pan fill one to work, but my main problem is gettin a deep sump pan, which they don't make for a pan fill, and also, my dipstick tube is WAY too short.

--Ryan
 



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So what is a case fill?
 






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