was just watching xtreme 4x4 season 1 (ep. where they build the WYOtech buggie)
they fabricated a square driveshaft by welding joints on 2 square steel piece
one steel piece fit inside the other for slip travel

it looked so easy and cheap. there's got to be an obvious reason why Ive never seen this on an xj before
horibble vibration? I wanna make one

 

if its on a daily driver it will vibrate like no other. it's been done many times on strict off road rigs

 

figures

 

Strictly for low speed use. Lots of ppl running home built budget buggies do it.

 

good for a front driveshaft if you run locking hubs, or low speed use.

 

cheap way to get a long slip shaft. vibrates, and makes noise.

 

They are perfect for people with unlocking hubs so it only spins when your wheeling at slow speed.
It requires a piece of 2.0 and 2.5 inch reciever hitch tube they have a tighter fit and are good up to 30-40 mph depending how good you build it.

My old boss used a pto shaft like you'd use on a tractor and made a shaft out of that for the front of his blazer.

 

I know plenty of guys running them in buggys and the ones around here are running high HP motors, 500+, and they work great but that's on dirt and rocks. On pavement they would be aweful. You can see them wobble as they are driving but when you're rock bouncing you don't worry too much about vibrations.