Don , I was just thinking the same thing, how did they grease the top joint? There is no zerk and to remove the shaft and disassemble the joint grease it and put it back in would be more time consuming then replacing the shaft.
The splines on mine were seized and making similar noise !

 

It didn't take them that long, only about 20 mins to grease what ever they did, so I don't think they disassembled anything.
@Oldblue, Did you fix it yourself? If so how did you do it.

 

Oh. I also forgot to add. When i had the underneath of the dash apart if i pushed up on the Rubber housing around the spline it seemed to go away or at least get quieter.

 

I do my own repairs, I replaced this this yoke was worn, and the splies off to the right of the picture were seized and very worn

 

How was it to replace? Any tips?

 

Ensure your wheels are pointing straight forward, mark the splines on the steering column were the yoke goes on, the rack end may require you to jack up the driver's side and place a jack stand under the car then remove the thru bolt and tap the yoke upwards off the steering rack double D shaft!
You already had the lower dash panel off so you know that part!