I have the borgeson shaft... It made my rattle go from only when turned to only when straight.
I pulled it and installed the stocker back, before I installed it, I took a die grinder and cleaned the swaged splines off, so the shaft could be slipped apart with out damaging the teflon splines. Cleaned all the grease off both the male and female splines.
I purchased a new plastic upper steering slip shaft carrier bearing from the dealer, its the one in the bottom of the steering column by your knees. The end of the steering slip shaft that goes into the cab slips into this cheesy plastic ball bearing.
The bearing will pull out by hand and install by hand. Take a 2" IIRC hose clamp and wrap it around the steel portion of the steering column where the cheesy bearing rides. Wait to tighten it until you put the shaft back in.
The old bearing version was white and the new updated version is green.
Install high temp silicone on both sets of grease free splines on the steering shaft and re-assemble. Install the shaft back in the truck and reconnect the ends before the rtv sets up, don't worry it takes a couple hours to cure...
Now tighten that clamp around the base of the steering column (the metal portion where new green plastic bearing is riding). The clamp keeps the column tight around the green bearing and the green bearing stays tighter around the cab end of the steering slip shaft.
The rtv won't pound out of the splines like the grease does and still moves and flexes the minimal amount you need for frame flex.
Anywho, long winded but it fixed my rattle.