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3speed to C4

BRONCO635

Jr. Member
Joined
Feb 8, 2010
Messages
136
So I’m kicking around the idea of swapping out my stock 3speed for a C4.
The thing is I want to swap with minimal modifications since my truck is a finished product now.
C4 same length as stock 3S?
Cross member trans bracket stay the same?
Driveshafts stay same length ?
Can it be a floor shift ?
Bolt right back up to factory D20?
Like I said ,my truck is completed and everything painted so I don’t wanna go and start hacking on it but don’t mind turning a few wrenches at this point.
C4 was a factory option so was hoping it would be a smooth up grade.
Any insight would be gratefully appreciated.
Thanks.


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Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Yes
Yes
Yes
Yes

All factory interchangeable stuff. You can even use a stock column shift and not have to cut up your floor.
Just have to find a Bronco C4, you need an adaptor for the D20. The 3-speed adaptor is not the same as the C4 adaptor.
 

Tiko433

Contributor
I know just enough to be dangerous
Joined
Jul 9, 2014
Messages
1,787
Loc.
South West Florida
If you need one let me know .. I have a floor shifter , cross member , bellhousing.., so on
 
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BRONCO635

BRONCO635

Jr. Member
Joined
Feb 8, 2010
Messages
136
If you need one let me know .. I have a floor shifter , cross member , bellhousing.., so on


I have the 3speed converted to the floor now already. That’s why I was wondering if I could go back to the floor for auto.
Will my current bell housing work?
Is the cross member different ?


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SteveL

Huge chevy guy
Joined
Jun 24, 2001
Messages
11,613
Loc.
Hawthorne ca
Bell housing is attached to the c-4. Will need different flywheel/flexplate and the starter is different. I'm getting ready to do the same swap.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
Starter, blockplate, flexplate, flexplate bolts, and keep going back.
Don't forget to remove the pilot bearing from the crank.
 

66ALRIDE

Contributor
Just BIP It!
Joined
May 9, 2005
Messages
1,785
Loc.
Dothan, AL
The C4 has a removable bellhousing. You’ll also need either a radiator with a transmission cooler or add a cooler if front of the radiator. Here is pic of the C4 out of my wrecked 74.
 

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66ALRIDE

Contributor
Just BIP It!
Joined
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Messages
1,785
Loc.
Dothan, AL
Like previous posts, you’ll need plate between engine block and C4. Remove the pilot bearing from crankshaft. You’ll need an adapter for Dana20 but the driveshafts should be the same. The cross member mounts to the Dana20 so it’s the same. Run lines and have a trans cooler and install a floor shift then you’ll be ready to go.
 

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Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
The block plate closes off the front of the bellhousing. It is also the index that correctly locates the starter to the flexplate so it doesn't scream like a cheby starter that needs shims nor flicks the teeth off the flexplate rendering you an engine that you have to bump over a little by hand before the starter will engage. People leave them out, but they are there for a reason.

And the bellhousing for the C4, it may be detachable but it is completely different than the one for the manual transmission. And there are various different C4 bellhousings. Both engine side and transmission side. The good part is most of the time they are just part of the transmission, not a separate add on piece. Only taken off to make servicing the transmission easier.
 

74 Bronco Billy

Contributor
Sr. Member
Joined
Jul 4, 2016
Messages
775
And with the flex plate is a ring with holes for the flex plate bolts. It must be used. It is called a flex plate stiffener by some, summit, Jegs will have them. And remember to seal the flex plate bolts. Definitely look up installing the torque converter, don’t put it in dry. The reverse switch and lockout is different I believe.
 

Tiko433

Contributor
I know just enough to be dangerous
Joined
Jul 9, 2014
Messages
1,787
Loc.
South West Florida
Yep. I have the plate, flex plate , starter , and so on ..... I did the same swap from a 3sp on the floor . I used a B&M shifter and mounted it where the 3 sp was. Had it running for a few years. I messed the TQ up pulling someone out of a ditch. As I thought about fixing it . I went with a AX 15 . Anyway my whole set up down to a cooler w/fan even a Temp gauge is sitting on a shelf if anyone is interested.
 
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BRONCO635

BRONCO635

Jr. Member
Joined
Feb 8, 2010
Messages
136
Wow guys. Thanks for all the replies.
Sorry to hear of your loss there 66ALRIDE.
I’ve read all the comments and it’s starting to sound like a scavenger hunt about to take place.
The cooler and lines and even shift parts don’t bother me.
It’s the bronco specific parts that are going to be interesting to find.
Like someone said there are different bell housing apparently just for bronco.
The section between the trans and t case has to be found as well.
The c4 I was looking at is a friend of mines that he was going to put in a Jeep project but never did.
So I’m going to have to investigate closer as to what he actually does have there.
Like I said I don’t mind chasing after market items it’s the “ford “and then “ford bronco” parts that’s confusing.
How would I know one bell housing from the others with out taking mine apart 1st of corse.
My thought was to start collecting items then once I’m ready swap it all over so not to leave the truck down too long.
Thanks again guys.


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Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,835
The C4 comes in so many different versions. There are 2 different cases (case fill and pan fill). The pan fill is the stronger of the cases. It also requires a different bellhousing than the case fill. The different bellhousing also brings on a different flexplate (164 tooth used intrucks vs 157 tooth used in cars). And there are various different internals used in the transmission as well.

The original Bronco has all the good parts all built in from the factory. If you find someone selling the whole package you are almost always ahead than trying to piece one together. If you have to piece one together look at bigger stuff, large cars and F100/150 from the early/mid 70s. Those usually had the pan fill case (dipstick bolts to the side of the transmission pan and not pushed into a hole in the case, makes a stronger transmission case).
 

66ALRIDE

Contributor
Just BIP It!
Joined
May 9, 2005
Messages
1,785
Loc.
Dothan, AL
The C4 should have the bellhousing already. It is detachable but most of the time still attached. I’ve used both the case fill and pan filled so either will work. The only thing you need to be aware of is if the C4 was for a 2wd you will have to change the output shaft and get the adapter for the Dana20. Other then that it’s not a complicated swap. If you’re building on a budget then the C4 is the way to go for an automatic in my opinion. If budget isn’t a huge concern then go with an AOD. With the AOD you’ll have to change driveshafts. I’ve got a 74 coming back to me that we first did a NV4500 standard in then changed over to an AOD. Now he’s decided to go Coyote 5.0 with the 6spd automatic. It may be a little while before he finishes getting all the parts together for the swap, but he will be selling the AOD.

As far as the wrecked Bronco no need to feel bad for me. I’ve been out of the Bronco building for a while and bought that one wrecked to rebuild. Well since I’ve bought that, I’ve bought 2 more. I’ll be using the wrecked for parts. You can find a thread on it but I’ve made any progress with it lately. Good luck with changing over to the C4, it’s pretty straight forward and you’ll be happy with it.
 
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BRONCO635

BRONCO635

Jr. Member
Joined
Feb 8, 2010
Messages
136
Something I should point out with all this also is the fact that I am running a new 5.0 fox body set up.
Which I had to get the correct felt wheel at that time.
So I guess I need the same balanced flex plate again for the swap.
Both my driveshafts are new so I don’t wanna get into changing them or cutting.
20/20 hind sight I shoulda just did the swap back when I finished the truck but to late now.
Like i say I was hoping for a literal swap out dimensionally and don’t mind adding coolers and lines ,that stuff doesn’t bother me.
Bottom line just looking for a more friendlier cruiser situation. My truck is a complete street truck so don’t need anything radical under it.
Thanks for the replies guys.


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sprdv1

Contributor
REBEL
Joined
Mar 8, 2007
Messages
81,734
May as well.. you'll love it

So I’m kicking around the idea of swapping out my stock 3speed for a C4.
The thing is I want to swap with minimal modifications since my truck is a finished product now.
C4 same length as stock 3S?
Cross member trans bracket stay the same?
Driveshafts stay same length ?
Can it be a floor shift ?
Bolt right back up to factory D20?
Like I said ,my truck is completed and everything painted so I don’t wanna go and start hacking on it but don’t mind turning a few wrenches at this point.
C4 was a factory option so was hoping it would be a smooth up grade.
Any insight would be gratefully appreciated.
Thanks.


Sent from my iPad using Tapatalk
 
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