Funny... your Q is at about 200k, same as mine when it failed. Brian is right... WD40 is a good diagnostic tool to get you by until the new one shows up. It amazes me how well that u-joint holds up given it's proximity to the exhaust manifold.
I think you're the second NICO Q owner that has replaced one of these, so it's not a really common problem - but it's definintely worth checking if you have p/s issues.
Heath
1990 Infiniti Q45 **** AKA "Q2"
2005 Infiniti G35 **** Sedan A/T
2004 Nissan Frontier.. King Cab M/T