I appreciate everyone's help, NH575E, Swetz, Jlap, and anyone else I may have missed.
I finally had the time to change out the oil and boy was it fun. I had no issues removing the fluid and my drain plug came out very easy. The suction filter was clean and everything went back together nicely.
After taking the side cover plate off so I could look inside the tank, of course the fluid was almost tan/white. Obviously not good. I did find it interesting that the sludge on the bottom of the tank was a thick and white, almost like a paste. It took me about an hour and a lot of rags to finally get it all out.
I changed out the fluid, filter, and added 23 gallons of Chevron THF 1000 back to the tank. I let the machine run for about 25 minutes working all of the controls and all was well.... so I thought.........
Yesterday I went out and worked the machine for about 6 hours and noticed halfway through that my original red/orangeish colored fluid in the sight glass was now a faintly tinted orange. Obviously I can do the math - if the system holds 36 gallons and I added 23, 33% was still left in the lines, pump, etc.... I guess I was just expecting a better outcome.
Looks like I will be spending more money on this thing come the fall time