Finally did the PSF change on the Rendezvous. Never has been changed, so it was in for at least 7 years. I got the white bottle of Valvoline PSF (which is completely clear in color), 2 quarts to just do siphon and refills. Its so cramped in the back of the reservoir to do a complete drain like I wanted so I decided to just do the siphoning. Way easier and less messy. Put the siphon in the black reservoir and pulled up the fluid. It was blacker than used oil! It was even crudding up on the bottom of PSF cap. Since I had 2 quarts and it only took 8oz on each drain and fill so I ended up doing 7. The last one was finally a nice light brown. I am going to get another quart and do a few more drain and fills in a few weeks. The steering is much smoother now and moving the wheel doesn't feel so tough now. Drives really nice. Any suggestions, for why it would be that grossly dirty, other than just never changed?