Okie Bushing History The Okie bushing was created by the long gone National Machine Works Inc in Oklahoma, hence the name Okie.
It shortened the time and effort to repair the torque tube bushings and oil seal.
If you did it the way GM did it, you would remove the entire torque tube from the rear axle.
Remove ring & pinion gears
Pull out the driveshaft from the torque tube.
Use special tools to remove and replace the bushings and oil seal.
Then reassemble everything. Pain in the Butt.
With the Okie bushing you just pull out the front bushing.
Then from the front of the torque tube you push in the Okie bushing sleeve, which has the Front bushing,
Rear bushing & Oil seal inside the sleeve. Less Work.
My Okie Bushing Photo Album Nice write up On The Okie Bushing By
tclederman 
