C4 swap, can't get a drive shaft to work

[blue83ranger]

Here's my situation, my truck is an '86 ranger extended cab 4x4 with a 2.9 and i swapped from an A4LD to a C4 and added a 4 inch suspension lift. The c4 is roughly 4 inches shorter than the A4LD. So i need a longer drive shaft so we went to a place that makes them and they said with my tire size (31's) and my gearing (stock 3.73's) that if they made a one piece drive shaft it would bow and eventually blow apart (has to be 67" 5/16 long) and they said for a once piece to work i would need a bigger pipe but because the u-joints on it are so small they can't make the pipe any bigger, meaning the bigger pipe won't physically fit on the smaller u-joint coupler, or what ever the piece is called the u joint is held in. So what would everyone suggest i do? 1 or 2 piece? how can i get a bigger pipe with u joints that could handle everything and still bolt up correctly?

 

[tnab1970]

I would like to know what you did for bell housing, flex plate, and converter ? I have been thinking about this swap myself, as I have killed a couple of A4ld's. Thanks

 

[tnab1970]

what rear end is in the truck ?

 

[samsonitesamsonite]

uhhhh I have a 3" lift 31"s and 3.73's (longbed 5 speed) and my one piece shaft doesn't have any problems at all.

 

[blue83ranger]

The rear end is just the stock 7.5 and i used all the parts that came from my '83 which had a C5 and we swaped out the tailhousing, bellhousing, etc and put it in a C4. I had it still in my '83 and put a 302 in it. But had to park it because of gas mileage.

 

[blue83ranger]

But an extended cab is longer to begin with and i have a 4 inch shorter transmission than i had before.

 

[metalmacguyver]

try another place and see if they say the same thing.

 

[Mutant Pony]

You need the flat flange for the back of the transfer, If you don't already have one. Then get two flanges from the rear of two wheel drive Rangers or Mustangs Driveshafts. Then a Half ton drive shaft will bolt right in.
My '86 RClb has a Full size Bronco drive shaft bolted in that way. (also 3.73 and 31's)

 

[AllanD]

His primary issue is that he has an '86 supercab and like all 86-88 supercab
it has the driveshaft with the "dinky" little U-joints (the ones where the grease seals for the cups almost touch each other.

What he needs is the shaft from an '87-ish 4x4 longbox that he can get extended as those use the next size up U-joints without getting into the issue that a '90-up driveshaft would add... '90-up the rear axles use a larger diameter pinion flange
and that gets into whole 'nother can of worms...

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[Mutant Pony]

The Rear end in his truck should have the flat flange already on it. The transfer may or may not, depending on which driveshaft it came with. The flange from the rear of the driveshaft on a two wheel drive will bolt to his rear end and uses the big u-joint. The only gen I 4x4 i've ever seen with the big rear u joint was an STX.

 

[blue83ranger]

I have a flange on the transfer case and on the rear. It seems like a bronco driveshaft would be to short. What are the specs on your truck with one? and i measured 4 driveshafts just to get an idea what i may need. Mine is 2 1/2 inches one out of a '83 2.0 ranger was about 2 3/4 and one from a fox mustang (hard to tell which car it came from, we have amany foxes) measured 3 inches. and for length i measured my dad's '89 f250 4x4 long bed and it was about 10 inches to short.

 

[Mutant Pony]

My truck is a RCLB. Or regular cab, long box. The bronco shaft fit mine. Yours is longer but, any full size 4x4 truck should be plenty long.
I am driving a SUPERCAB Ranger as a DD. I have been planning to do the same swap but, haven't got there yet. Of coarse mine will be 2" shorter. (fm145)
I worked in a Junk yard when I built my truck, I grabbed parts from here and there and bolted it together. I don't have any idea what year or option package the bronco was- the shaft just has Bronco wrote on it.
Measure the flange on the back of the transfer. Is it a different pattern than the one on the rear end?

 

[Mutant Pony]

I just went to the Garage and measured. Your Ranger should be a 2 1/2" pattern on both ends. I have an '84 turbo coupe drive shaft with that pattern and the big joint. I also have a 2wd Ranger driveshaft with that bolt pattern and the big joint. I also have a '87 t-bird drive shaft with a 3" bolt pattern so the key is to look for a 2 1/2" bolt pattern with the big joint.
Now. I've had that same u-joint in dozens of different vehicles dating back into the sixties. although the 1/2 ton driveshafts I have here use an even bigger joint. I think the first thing you need to do is find the drive shafts with the big joints and the 2 1/2" pattern, buy new U-joints then You will probably have to search for a shaft that will either bolt or can be cut down.
Also, If you find a driveshaft that is to short, A longer tube can be put in it.

 

[Mutant Pony]

Got it! Second trip to the garage solved it. 1/2 ton 4x4 front drive shaft. The tube will be to short but, it is a common 2 3/4 tube size. Same u-joints as the 2wd Ranger. Remeasure that 2.0 ranger shaft- the bolt pattern should be 2 1/2.
A shaft from a town car may work, you would just have to have the slider put it one end.
Also, The carrier bearing crossmember will need to be cut out.

 

[bottledgt]

i needed a 67 inch also.(331/aod swap). shop told me the same thing. dont cheap out on this. i threw one shaft out before i had them make me a 2 piece. i dont think people realize your driveshaft spins alot faster with low gears. mine didnt vibrate a bit until i hit about 80 one day,then in about half a second it came out. i now have a 2 piece 3 inch shaft. takes a little to set up right, but when you're done ,its right.