View Full Version : Rear End U-Joint Connection

11-18-2013, 11:12 AM
Our cars use a companion flange and U-joint adapter to connect the rear u-joint on the drive shaft to the rear end pinion.

There is a fair amount of discussion online on mustang and 4x4 sites about this type of connection being inferior to a yoke and the companion flanges/adapters failing although I cant find alot of discussion about actual failures.

I'm building the new solid axle rear and was hoping to reuse my existing driveshaft and companion flange/adapter setup. Now I'm not sure the driveshaft length works but should I be replacing the companion flange anyway regardless of whether the drive shaft works or not.

Car is about 3200# and makes over 500rwhp.

Strange makes a forged chromoly yoke where the u-joint is retained with u-bolts for about $100 and Mark Williams also makes a billet piece that has bearing caps to retain the u-joint in stead of u-bolts (SEXY) but its more like $300. Both of these options use the 1350 u-joints.


Mark Williams:

I'll spend the money if it's worth doing but I've never heard of one of our companion flanges or u-joints failing so I'm thinking it might not be worth the extra $$.

11-18-2013, 11:34 AM
Can't say I recall any cobra guys breaking the flange. But if you have to change the drive shaft might as well go bigger and better.

I guess Kevin would be the guy to answer this question. And maybe Siska will chime in on which way he went. Casey too but he hasn't tested his yet.

11-18-2013, 12:02 PM
I'm with you.....

If I find I have to change the drive shaft because it is the wrong length then I'll upgrade everything no questions.

But if the flange/adapter is no good then I get into replacing the drive shaft and upgrading regardless if the shaft could work or not.

11-18-2013, 12:46 PM
The custom aluminum Dennys driveshaft I used when the car was IRS was reused on my solid axle swap. The length was right and I stayed with the stock style rear companion flange.


11-18-2013, 03:19 PM
That's what I was hoping to hear right there!!!!!!

pro street rich
11-19-2013, 10:33 AM
There is no replacement for something stronger. When I do these bbf swaps I always have a new shaft made and add the slip yoke to it. I also get the biggest u-joint I can fit in there. This just makes sence to me to build it once instead of rebuilding the car after you break the drive shaft and whatever else goes along with it.....Rich